Index: generic/tkText.c
==================================================================
--- generic/tkText.c
+++ generic/tkText.c
@@ -1489,10 +1489,11 @@
 		if (result == TCL_OK) {
 		    /*
 		     * Move the insertion position to the correct place.
 		     */
 
+                    indexFromPtr = TkTextGetIndexFromObj(interp, textPtr, objv[2]);
 		    TkTextIndexForwChars(NULL, indexFromPtr,
 			    deleteInsertOffset, &index, COUNT_INDICES);
 		    TkBTreeUnlinkSegment(textPtr->insertMarkPtr,
 			    textPtr->insertMarkPtr->body.mark.linePtr);
 		    TkBTreeLinkSegment(textPtr->insertMarkPtr, &index);

Index: tests/text.test
==================================================================
--- tests/text.test
+++ tests/text.test
@@ -1572,10 +1572,20 @@
 test text-8.26 {TextWidgetCmd procedure, "replace" option crash} -setup {
     text .tt
 } -body {
     .tt insert 0.0 foo\n
     .tt replace end-1l end bar
+} -cleanup {
+    destroy .tt
+} -result {}
+test text-8.27 {TextWidgetCmd procedure, "replace" option crash} -setup {
+    text .tt
+} -body {
+    .tt insert 0.0 \na
+    for {set i 0} {$i < 2} {incr i} {
+        .tt replace 2.0 3.0 b
+    }
 } -cleanup {
     destroy .tt
 } -result {}