Abstract: The aim of this study is to assess the effects of Olive Oil Mill Wastewater (OOMW) application as irrigation water on in vitro pollen germination, focusing on total protein quantity. In test groups, pollen germination substances such as sucrose, H3BO3 and Ca(NO3)2 were added to different concentrations of OOMW and used as germination media. Regarding control group, the same substance melted into water instead of OOMW. As a result, in general, pollen germination percentage was decreased significantly in all OOMW concentrations than that of the control group, except 1/1000 concentrations. Similarly, total protein quantities declined linearly depending on decreasing OOMW concentrations, except 1/1 concentration which has 4-5 times the control value. Consequently, it was established that OOMW generally decreased pollen germination ratio and had carcinogenic effects on protein synthesis mechanism and must not be used as irrigation water without purification.