With this study, it is aimed to determine the volumetric changes at kidneys of 40 sheep (left and right kidneys, in total 80 kidneys) before and after treated with different fixation solutions by using a stereological method. In the study, 80 sheep kidneys provided from our faculty slaughterhouse were used. Kidneys were divided into four groups of 20 kidneys in each group (10 left and 10 right kidneys). During slaughtering of the sheeps, kidneys were rapidly taken out from abdominal cavity of the animal and fresh kidneys volumes which sectioned to 0.5 cm thickness were determined by Cavalieri Principle. It was noticed that this process did not exceed 30 min in order to prevent autolysis. Afterwards, groups of kidneys each including 20 were put into Formalin, Ethyl alcohol, Zenker and Bouin solutions and fixed upon determinated fixing durations. Volume redeterminations by using Cavalier Method were also performed on fixed kidney cross sections. Number of intersected points and other parameters were entered to the macro program (Microsoft Excel XP) and volumes were determined. Volumetric changes occured on kidneys before and after fixation were evaluated, and statistical calculations were performed. It was observed that all of the fixing solutions used in this study have different rate of diminish effect on kidney volume. However this effect were not statistically significant. The evaluation of interaction on volume changes; solution, direction and solution x direction were also not significant (P>0.05). We think that data gathered at anatomical and histological research using fixed materials may be used as references.