Introduction: We evaluated the relation between ischemic priapism (IP) and blood count parameters in IP patients. We especially wanted to examine the contribution of eosinophil count (EC), platelet count (PC), and mean platelet volume (MPV) values, which are suspected predictive parameters for vascular endothelium damage and venoocclusive pathogenesis and etiopathogenesis, particularly in IP. Methods: A total of 40 IP patients fulfilled the study criteria. Forty healthy volunteers in a similar age group were included as the control group. Complete blood count values were compared between the two groups. Intergroup comparisons were performed using the Mann-Whitney U test, and the chi-square test was used to assess the relationship between categorical variables in the patient groups. The area under the curve was calculated by receiver operating characteristic (ROC) regression analyses. Epidemiological diagnosis percentages were calculated by finding cutoff values. Results: The IP group's high MPV, PC, and EC values compared to those of the control group were detected to be statistically significant (p<0.001, p=0,03, p=0.001, respectively). No statistically significant difference was observed between the two groups for other blood count parameters. Statistically significant values for IP were measured as MPV: positive predictive value: 84%; EC: positive predictive value: 71.4%; and PC: positive predictive value: 61.4%. Conclusions: High MPV, PC, and EC values are significant positive predictive factors in IP etiopathogenesis. No proof was detected for other blood count parameters playing an active role in IP etiopathogenesis.