diff --git a/docs/changes/1.2.0.md b/docs/changes/1.2.0.md
index 4247f38b8..25cc38199 100644
--- a/docs/changes/1.2.0.md
+++ b/docs/changes/1.2.0.md
@@ -17,6 +17,7 @@
 - `phpoffice/phpspreadsheet`: Allow version 4.0 by [@nreynis](https://github.com/nreynis) in [#861](https://github.com/PHPOffice/PHPPresentation/pull/861)
 - Smaller package size by [@nreynis](https://github.com/nreynis) in [#862](https://github.com/PHPOffice/PHPPresentation/pull/862)
 - Added setFirstSliceAngle to Doughnut Chart by [@seanlynchwv](http://github.com/seanlynchwv) in [#872](https://github.com/PHPOffice/PHPPresentation/pull/872)
+- Added ability to set rounded corner radius by [@seanlynchwv](http://github.com/seanlynchwv) in [#880](https://github.com/PHPOffice/PHPPresentation/pull/880)
 
 ## Bug fixes
 
diff --git a/src/PhpPresentation/Shape/AutoShape.php b/src/PhpPresentation/Shape/AutoShape.php
index 4bb6b1237..a12df299e 100644
--- a/src/PhpPresentation/Shape/AutoShape.php
+++ b/src/PhpPresentation/Shape/AutoShape.php
@@ -273,4 +273,31 @@ public function setOutline(Outline $outline): self
 
         return $this;
     }
+
+    /** @var null|int */
+    private $roundRectAdj;
+
+    public function getRoundRectAdj(): ?int
+    {
+        return $this->roundRectAdj;
+    }
+
+    /**
+     * Set corner radius.
+     */
+    public function setRoundRectCorner(int $pixels): self
+    {
+        $minHalf = (int) floor(min($this->width, $this->height) / 2);
+        if ($minHalf > 0) {
+            $this->roundRectAdj = max(0, min(50000, (int) round($pixels / $minHalf * 50000)));
+        }
+
+        return $this;
+    }
+
+    // override the hash so radius works
+    public function getHashCode(): string
+    {
+        return md5(parent::getHashCode() . $this->type . $this->text . (string) $this->roundRectAdj . __CLASS__);
+    }
 }
diff --git a/src/PhpPresentation/Writer/PowerPoint2007/AbstractSlide.php b/src/PhpPresentation/Writer/PowerPoint2007/AbstractSlide.php
index 2f0544fd7..678209033 100644
--- a/src/PhpPresentation/Writer/PowerPoint2007/AbstractSlide.php
+++ b/src/PhpPresentation/Writer/PowerPoint2007/AbstractSlide.php
@@ -1187,9 +1187,21 @@ protected function writeShapeAutoShape(XMLWriter $objWriter, AutoShape $shape, i
         // p:sp\p:spPr\a:prstGeom
         $objWriter->startElement('a:prstGeom');
         $objWriter->writeAttribute('prst', $shape->getType());
-        // p:sp\p:spPr\a:prstGeom\a:avLst
-        $objWriter->writeElement('a:avLst');
-        // p:sp\p:spPr\a:prstGeom\
+
+        // a:avLst (+ optional adj for roundRect)
+        $needsAdj = ($shape->getType() === AutoShape::TYPE_ROUNDED_RECTANGLE);
+        $adj = $shape->getRoundRectAdj();
+
+        if ($needsAdj && $adj !== null) {
+            $objWriter->startElement('a:avLst');
+            $objWriter->startElement('a:gd');
+            $objWriter->writeAttribute('name', 'adj');
+            $objWriter->writeAttribute('fmla', 'val ' . (string) $adj); // 0..50000
+            $objWriter->endElement(); // a:gd
+            $objWriter->endElement(); // a:avLst
+        } else {
+            $objWriter->writeElement('a:avLst');
+        }
         $objWriter->endElement();
         // Fill
         $this->writeFill($objWriter, $shape->getFill());
diff --git a/tests/PhpPresentation/Tests/Shape/AutoShapeTest.php b/tests/PhpPresentation/Tests/Shape/AutoShapeTest.php
index cd601562d..d9c2e173d 100644
--- a/tests/PhpPresentation/Tests/Shape/AutoShapeTest.php
+++ b/tests/PhpPresentation/Tests/Shape/AutoShapeTest.php
@@ -20,9 +20,14 @@
 
 namespace PhpOffice\PhpPresentation\Tests\Shape;
 
+use PhpOffice\PhpPresentation\PhpPresentation;
 use PhpOffice\PhpPresentation\Shape\AutoShape;
+use PhpOffice\PhpPresentation\Style\Color;
+use PhpOffice\PhpPresentation\Style\Fill;
 use PhpOffice\PhpPresentation\Style\Outline;
+use PhpOffice\PhpPresentation\Writer\PowerPoint2007;
 use PHPUnit\Framework\TestCase;
+use ZipArchive;
 
 class AutoShapeTest extends TestCase
 {
@@ -64,4 +69,83 @@ public function testType(): void
         self::assertInstanceOf(AutoShape::class, $object->setType(AutoShape::TYPE_HEXAGON));
         self::assertEquals(AutoShape::TYPE_HEXAGON, $object->getType());
     }
+
+    public function testPixelSetterComputesAdjAndAffectsHash(): void
+    {
+        $width = 200;  // px
+        $height = 100;  // px
+        $px1 = 5;  // softer radius
+        $px2 = 10; // larger radius
+
+        $shape1 = (new AutoShape())
+            ->setType(AutoShape::TYPE_ROUNDED_RECTANGLE)
+            ->setWidth($width)
+            ->setHeight($height)
+            ->setRoundRectCorner($px1);
+
+        $shape2 = (clone $shape1)->setRoundRectCorner($px2);
+
+        // adj expected: round(px / (min(w,h)/2) * 50000)
+        $minHalf = (int) floor(min($width, $height) / 2); // 50
+        $expectedAdj1 = (int) round($px1 / $minHalf * 50000); // 5/50 * 50000 = 5000
+        $expectedAdj2 = (int) round($px2 / $minHalf * 50000); // 10/50 * 50000 = 10000
+
+        self::assertSame($expectedAdj1, $shape1->getRoundRectAdj());
+        self::assertSame($expectedAdj2, $shape2->getRoundRectAdj());
+
+        // Hash must differ when radius differs
+        self::assertNotSame($shape1->getHashCode(), $shape2->getHashCode());
+    }
+
+    public function testNoRadiusByDefaultIsNull(): void
+    {
+        $shape = new AutoShape();
+        self::assertNull($shape->getRoundRectAdj());
+    }
+
+    public function testWriterEmitsAdjGuideForRoundRect(): void
+    {
+        $ppt = new PhpPresentation();
+        $slide = $ppt->getActiveSlide();
+
+        $width = 200;
+        $height = 100;
+        $padding = 5;
+        $minHalf = (int) floor(min($width, $height) / 2);
+        $expectedAdj = (int) round($padding / $minHalf * 50000); // 5000
+
+        $shape = (new AutoShape())
+            ->setType(AutoShape::TYPE_ROUNDED_RECTANGLE)
+            ->setWidth($width)->setHeight($height)
+            ->setRoundRectCorner($padding);
+
+        // Give it a fill so it's an obvious shape
+        $shape->getFill()->setFillType(Fill::FILL_SOLID)->setStartColor(new Color('FFFFFFFF'));
+        $slide->addShape($shape);
+
+        $tmpFile = tempnam(sys_get_temp_dir(), 'pptx_');
+        $writer = new PowerPoint2007($ppt);
+        $writer->save($tmpFile);
+
+        // Open the pptx and read slide1.xml
+        $zip = new ZipArchive();
+        self::assertTrue($zip->open($tmpFile) === true, 'Failed to open pptx zip');
+        $xml = $zip->getFromName('ppt/slides/slide1.xml');
+        $zip->close();
+        @unlink($tmpFile);
+
+        self::assertIsString($xml);
+
+        // Must contain roundRect geometry and the adj guide with expected value
+        self::assertStringContainsString('<a:prstGeom prst="roundRect">', $xml);
+
+        // fmla="val N" (there is a space after 'val' in writer)
+        self::assertSame(
+            1,
+            preg_match(
+                sprintf('/<a:gd[^>]+name="adj"[^>]+fmla="val %d"/', $expectedAdj),
+                (string) $xml
+            )
+        );
+    }
 }
diff --git a/tests/PhpPresentation/Tests/Writer/ODPresentation/ObjectsChartTest.php b/tests/PhpPresentation/Tests/Writer/ODPresentation/ObjectsChartTest.php
index bd5dd4ad6..6c86e7558 100644
--- a/tests/PhpPresentation/Tests/Writer/ODPresentation/ObjectsChartTest.php
+++ b/tests/PhpPresentation/Tests/Writer/ODPresentation/ObjectsChartTest.php
@@ -578,7 +578,7 @@ public function testTypeAxisTickLabelPosition(): void
 
     public function testTypeAxisUnit(): void
     {
-        $value = mt_rand(0, 100);
+        $value = max(1, mt_rand(0, 100));
 
         $series = new Series('Downloads', $this->seriesData);
         $line = new Line();