Logical errors are the program bugs that are caused due to the programmer's faulty reasoning. Logical errors in a program are not easy to find since the point of failure is shown in a statement but actual bug may be in any other statement(s). Debugging of this kind of errors is tedious. To debug the logical errors backward slicing is very useful. But, in most cases, backward slices are as large as the original program itself. This again creates problem in finding the original bug. This paper presents Optimized Call-stack Restricted slicing which reduces the number of lines to be checked while debugging. In other words, this technique reduces the size of the slice and also ensures that Optimized Call-Stack Restricted slices are smaller than the slices produced by any other slicing techniques. Optimized Call-stack restricted slicing is very effective. The size of slice ranges from 3 to 80 percent of the original program. Under any circumstances, the size of slices produced by optimized call stack restricted slicer is not greater than that of other slicers. © 2011 Springer-Verlag.