The increasing prevalence of male subfertility and the possible association with the increasing rates of obesity is alarming. Fluid homeostasis in the testis is important for male fertility. This study aims to define the effect of diet induced metabolic syndrome on the testis and expression of the selective water channel AQP8. Materials and methods: 12 male Sprague-Dawley albino rats were divided equally into control and high fat high fructose diet (HFFD) groups. After 12 weeks, the blood glucose, insulin, lipid profile and testosterone level were evaluated. Liver and testicular sections stained with H&E for histopathological examination. Testis sections were immunohistochemically stained with anti-AQP8 antibody. The sperm of the cauda epididymis was analyzed. Results: in comparison to control, blood glucose of HFFD rats was elevated and insulin level was decreased. Serum triglycerides, cholesterol and LDL levels were significantly elevated while testosterone level was decreased. There was a significant decrease in sperm number and motility with increase of abnormal forms. Liver sections confirmed hepatic steatosis. Testes of HFFD group showed distortion of many seminiferous tubules, depletion of germ cells with exfoliation of cells into the lumen. The diameter and thickness of the tubules were reduced. Also, the immunoexpression of AQP8 was significantly decreased in comparison to control especially in relations to spermatids. Conclusion: AQP8 immunoexpression was decreased in the HFFD rats which might partially contribute to the reduced sperm quality. Other factors might also contribute to the changes in sperm and seminiferous tubules morphology like hormonal changes, hyperlipidemia and hypoinsulinemia.