The cumulus-oocyte complex (COC) is a structure that connects the oocyte (germline) with the surrounding cumulus cells. The diameter of fully grown human egg is 110 to 120 microns with a volume of approximately 900,000 cubic microns. The COC must be removed (denuded) before intra-cytoplasmic sperm injection (ICSI) in order to evaluate the mature oocytes and to be able for injection, the denudation of COC is done by enzymatic treatment and mechanical stripping. The vigorous mechanical stripping or using small diameter pipette may cause; displacement of the polar body and impair the microtubule frame. The actin filament organization causes the break of cellular bridge that connects the polar body to the oocyte, deformation and damage of the oocyte cytoskeleton impairing its ability to sustain correct pronuclear formation or may result in zona pellucida fraction and oocyte degeneration. In this study, 1756 oocytes were collected from 90 cycles, and oocytes divided into 2 groups. The first group of oocytes was mechanically denuded with pipette diameter 150 µm, and the second group of oocytes was denuded with pipette diameter 200 µm. This manipulation showed no statistical differences in the number of oocytes that degenerated during denudation, normal and abnormal fertilization and in the rate of blastocyst formation when using denudation pipette of 150 µm over that of 200 µm (p >0.05).