The treatment of pain in patients with impaired renal function may be problematic, especially when opioid drugs need to be used. In the presence of renal failure, significant changes occur in the metabolism and pharmacokinetics of these drugs, which can lead to adverse reactions due to the accumulation of parental compounds and active metabolites. This paper presents and discusses the available evidence concerning the optimal use of the most frequently employed opioid analgesics to treat pain in patients with renal impairment.