Pain in patients with impaired renal function may be a significant problem requiring treatment with opioids. However, pharmacokinetic and metabolic changes associated with an impaired renal function may raise some concerns about side effects and overdosing associated with opioid agents in this patient's population. In order to give recommendations on this issue, we review the available evidences on the pharmacokinetics and side effects of most common opioids used to treat pain. The results of this review show that the half-life of the parent opioid compounds and of their metabolites is increased in the presence of renal dysfunction, for which careful monitoring of the patient, dose reduction and a longer time interval between doses are recommended. Among opioids, morphine and codeine used with very caution and possibly avoided in renal failure/dialysis patients; tramadol, hydromorphone and oxycodone can be used with caution and close patient's monitoring, whereas transdermal buprenorphine, methadone and fentanyl/sufentanil appear to be safe to use in patients with renal failure.