BACKGROUND Since its introduction in France, ketoprofen for topical use has been associated with a large number of cutaneous adverse effect reports. Therefore, the French Medicine Agency progressively introduced warnings and contraindications to its use. Despite this, serious adverse drug reactions (ADRs) still occur. OBJECTIVE To describe clinical patterns and estimate costs of spontaneously reported cutaneous ADRs of topical ketoprofen. METHODS All cases of cutaneous ADRs of topical ketoprofen reported to the Bordeaux regional pharmacovigilance center between January 1989 and December 2006 were included. Clinical patterns, in respect of adherence to recommendations, causality, seriousness, and direct costs incurred by the ADRs, were assessed. RESULTS A total of 136 cases were reported (median age: 42 years, 55.9% women). Proper use of topical ketoprofen regarding indications, warnings, and contraindications was not respected by one-third of the patients. Almost all cases occurred during sunny months. Symptoms consisted predominantly of bullous eruptions (29.4%) or contact dermatitis (27.2%). Generalized lesions were observed in 37.5% of patients. Causality was considered at least possible for most of the cases (92.6%). These ADRs induced hospital admission in 15 cases (11.0%). The total estimated cost was euro 42,962 ($US 66,559), corresponding to euro 316 per case. This mean cost was nine times higher for serious ADRs. CONCLUSIONS Topical ketoprofen is used to treat benign symptoms but can be associated with serious and costly cutaneous ADRs. Furthermore, the number of cases and the calculated costs may have been greatly under-estimated in the present study.