diff --git a/CHANGELOG.md b/CHANGELOG.md
index 22216ca69a..f30f2da4c1 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -15,6 +15,8 @@ stage is computed (`ARKodeSetPreprocessStepFn`, `ARKodeSetPostprocessStepFn`,
 should treat the state vector as read-only, otherwise all theoretical guarantees of
 solution accuracy and stability will be lost.
 
+Removed extraneous copy of output vector when using ARKODE in ``ARK_ONE_STEP`` mode.
+
 ### Bug Fixes
 
 Fixed a CMake bug where the SuperLU_MT interface would not be built and
diff --git a/doc/shared/RecentChanges.rst b/doc/shared/RecentChanges.rst
index 9194c08ced..749f045051 100644
--- a/doc/shared/RecentChanges.rst
+++ b/doc/shared/RecentChanges.rst
@@ -15,6 +15,8 @@ These are considered **advanced** functions, as they should treat the state vect
 read-only, otherwise all theoretical guarantees of solution accuracy and stability
 will be lost.
 
+Removed extraneous copy of output vector when using ARKODE in ``ARK_ONE_STEP`` mode.
+
 **Bug Fixes**
 
 Fixed a CMake bug where the SuperLU_MT interface would not be built and
diff --git a/src/arkode/arkode.c b/src/arkode/arkode.c
index 2793ac89f9..36d5759d45 100644
--- a/src/arkode/arkode.c
+++ b/src/arkode/arkode.c
@@ -1148,13 +1148,12 @@ int ARKodeEvolve(void* arkode_mem, sunrealtype tout, N_Vector yout,
       break;
     }
 
-    /* In ONE_STEP mode, copy y and exit loop */
+    /* In ONE_STEP mode, exit loop (arkCompleteStep already copied yn to ycur, an alias to yout) */
     if (itask == ARK_ONE_STEP)
     {
       istate            = ARK_SUCCESS;
       ark_mem->tretlast = *tret = ark_mem->tcur;
-      N_VScale(ONE, ark_mem->yn, yout);
-      ark_mem->next_h = ark_mem->hprime;
+      ark_mem->next_h           = ark_mem->hprime;
       break;
     }
 
diff --git a/src/arkode/arkode_root.c b/src/arkode/arkode_root.c
index 5d621987ad..5714e87de0 100644
--- a/src/arkode/arkode_root.c
+++ b/src/arkode/arkode_root.c
@@ -471,8 +471,9 @@ int arkRootCheck1(void* arkode_mem)
   hratio = SUNMAX(rootmem->ttol / SUNRabs(ark_mem->h), TENTH);
   smallh = hratio * ark_mem->h;
   tplus  = rootmem->tlo + smallh;
-  N_VLinearSum(ONE, ark_mem->yn, smallh, ark_mem->fn, ark_mem->ycur);
-  retval = rootmem->gfun(tplus, ark_mem->ycur, rootmem->ghi, rootmem->root_data);
+  N_VLinearSum(ONE, ark_mem->yn, smallh, ark_mem->fn, ark_mem->tempv4);
+  retval = rootmem->gfun(tplus, ark_mem->tempv4, rootmem->ghi,
+                         rootmem->root_data);
   rootmem->nge++;
   if (retval != 0)
   {
@@ -533,11 +534,11 @@ int arkRootCheck2(void* arkode_mem)
   /* return if no roots in previous step */
   if (rootmem->irfnd == 0) { return (ARK_SUCCESS); }
 
-  /* Set ark_ycur = y(tlo) */
-  (void)ARKodeGetDky(ark_mem, rootmem->tlo, 0, ark_mem->ycur);
+  /* Set tempv4 = y(tlo) */
+  (void)ARKodeGetDky(ark_mem, rootmem->tlo, 0, ark_mem->tempv4);
 
   /* Evaluate root-finding function: glo = g(tlo, y(tlo)) */
-  retval = rootmem->gfun(rootmem->tlo, ark_mem->ycur, rootmem->glo,
+  retval = rootmem->gfun(rootmem->tlo, ark_mem->tempv4, rootmem->glo,
                          rootmem->root_data);
   rootmem->nge++;
   if (retval != 0) { return (ARK_RTFUNC_FAIL); }
@@ -569,7 +570,7 @@ int arkRootCheck2(void* arkode_mem)
   if ((tplus - ark_mem->tcur) * ark_mem->h >= ZERO)
   {
     /* hratio = smallh/ark_mem->h; */
-    N_VLinearSum(ONE, ark_mem->ycur, smallh, ark_mem->fn, ark_mem->ycur);
+    N_VLinearSum(ONE, ark_mem->tempv4, smallh, ark_mem->fn, ark_mem->ycur);
   }
   else
   {
@@ -632,24 +633,24 @@ int arkRootCheck3(void* arkode_mem, sunrealtype tout, int itask)
   if (itask == ARK_ONE_STEP)
   {
     rootmem->thi = ark_mem->tcur;
-    N_VScale(ONE, ark_mem->yn, ark_mem->ycur);
+    N_VScale(ONE, ark_mem->yn, ark_mem->tempv4);
   }
   if (itask == ARK_NORMAL)
   {
     if ((tout - ark_mem->tcur) * ark_mem->h >= ZERO)
     {
       rootmem->thi = ark_mem->tcur;
-      N_VScale(ONE, ark_mem->yn, ark_mem->ycur);
+      N_VScale(ONE, ark_mem->yn, ark_mem->tempv4);
     }
     else
     {
       rootmem->thi = tout;
-      (void)ARKodeGetDky(ark_mem, rootmem->thi, 0, ark_mem->ycur);
+      (void)ARKodeGetDky(ark_mem, rootmem->thi, 0, ark_mem->tempv4);
     }
   }
 
   /* Set rootmem->ghi = g(thi) and call arkRootfind to search (tlo,thi) for roots. */
-  retval = rootmem->gfun(rootmem->thi, ark_mem->ycur, rootmem->ghi,
+  retval = rootmem->gfun(rootmem->thi, ark_mem->tempv4, rootmem->ghi,
                          rootmem->root_data);
   rootmem->nge++;
   if (retval != 0) { return (ARK_RTFUNC_FAIL); }
@@ -861,8 +862,8 @@ int arkRootfind(void* arkode_mem)
       tmid    = rootmem->thi - fracsub * (rootmem->thi - rootmem->tlo);
     }
 
-    (void)ARKodeGetDky(ark_mem, tmid, 0, ark_mem->ycur);
-    retval = rootmem->gfun(tmid, ark_mem->ycur, rootmem->grout,
+    (void)ARKodeGetDky(ark_mem, tmid, 0, ark_mem->tempv4);
+    retval = rootmem->gfun(tmid, ark_mem->tempv4, rootmem->grout,
                            rootmem->root_data);
     rootmem->nge++;
     if (retval != 0) { return (ARK_RTFUNC_FAIL); }