Background: Diabetes and ageing are associated with erectile dysfunction (ED). Under these conditions, increased oxidative stress produces superoxide ions, which in turn suppresses the nitric oxide-cyclic guanosine monophosphate pathway. The phophodiesterase-5 (PDE5) inhibitors still remain ineffective in 15 – 57% of impotent men. Objective: To identify the efficacy of conventional and novel PDE5 inhibitors on oxidative stress involved in diabetes and ageing. Methods: An electronic search of the literature was conducted to review published information relating diabetes and ageing to ED and to cover late-stage developments of novel PDE5 inhibitors. Results/conclusion: Safe and more efficacious alternatives that can modulate PDE5 levels in ED regarding oxidative stress conditions are needed. Included in this review are updates on the new PDE5 inhibitors avanafil, udenafil, SLx-2101, and mirodenafil.