Cytopathology plays a significant role in cancer diagnostics. One of the ancillary methods used for prognostication is immunocytochemistry (ICC). Formalin pre-fixed tissue blocks are often used as validated immunohistochemical controls for cytology samples. However, those are not treated as clinical cytology specimen, which are furthermore commonly fixed in alcohol. As cell structure might be affected by added fixatives and block materials, the aim of this project was to compare the effects of fixation in formalin and PreservCyt®, a methanol-based fixative, and the two cell block materials, plasma-thrombin and agar, on the ICC results. The material used in the study consisted of several cell lines provided by the Technological University Dublin, which were chosen to be representative of the clinical cytology samples. The cells were fixed and put into cell blocks for each cell type or as a mixture of different cell types – a composite cell block. All cell blocks were then stained with suitable antibodies. Composite cell blocks could be tested as simultaneously positive and negative ICC control material. The results showed that in general, PreservCyt®-fixed cell blocks preserved sharper cellular morphology compared to those fixed in formalin. However, PreservCyt® also gave unexpected negative results for some antibodies, including some nuclear markers. Plasma-thrombin cell block method showed to have more advantages than the agar method.This study suggests, that with further optimization and validation of both fixative methods and cell blocks, composite cell block has good potential to be used as source of control blocks for cytology samples.