Patients with type 2 diabetes mellitus (DM) have more disturbances of sexual and reproductive functions. The consequences of type 2 DM may include dyslipidemia, insulin resistance (IR), cardiovascular disease (CVD) and low testosterone level. The main objective of this study is to determine the value of various biochemical parameters in relation to erectile dysfunction (ED) in type 2 DM patients in Gaza city, Palestine. A total of 160 males between the age of 35–60 years were recruited; 80 type 2 DM patients and 80 as controls. Anthropometric, demographic, sexual and clinical data were obtained by questionnaire. Increased prevalence of high BMI and HOMA-IR were observed among type 2 DM patients, while high incidence of low testosterone was found in the same group (p< 0.05). Testosterone was correlated negatively and significantly with BMI and duration of type 2 DM (p< 0.05). ED was correlated significantly and directionally with dyslipidemia, duration of type 2 DM, and complications of diabetes mainly retinopathy (p< 0.05). While, nocturnal/early morning erection (NEME) was correlated significantly but inversely with duration of type 2 DM (p< 0.05). In addition, fasting blood glucose (FBG), duration of type 2 DM and low level of testosterone were predictor factors associated with ED (p< 0.05), while increased BMI was a predictor factor associated with low testosterone level (p< 0.05). In the present study, high incidence of low testosterone and increased prevalence of ED among type 2 DM patients could be attributed to uncontrolled type 2 DM, obesity, IR, dyslipidemia, long duration of type 2 DM and its complications
