Background: Both testosterone and dihydrotestosterone are necessary for normal penile growth, 
which is positively correlated with the increasing testosterone concentrations during puberty. The 
penis tends to undergo an actual and irreversible reduction in size as man ages. Aim: to measure the 
stretched penile length (SPL) in aging males and correlate the result with their serum level of total 
testosterone. Patients and methods: 103 patients were recruited then SPL was measured and serum 
was collected for testosterone measurement. Results: SPL has a non significant correlation with age, 
while serum testosterone show significant decrease with age. Conclusion: Penile length does not 
decrease in males with aging, while serum level of testosterone does.