The accuracy of diagnosis of femoral hernia in referrals to a district general hospital over a period of 5 years has been studied and related to clinical outcome. A correct diagnosis was made in only 36 of 98 cases (60 urgent, 38 routine) before admission to hospital. A correct pre-operative diagnosis was ultimately made in 85 cases. Four patients, all urgent admissions with incarcerated bowel, died within 30 days of operation. In none of these cases was a correct diagnosis made before admission to hospital. The median length of post-operative stay of urgent admissions was 7 days (range 4-50) when a correct initial diagnosis was made and 10 days (range 4-50) when the initial diagnosis was incorrect (P = 0.07, Mann-Whitney test). When strangulated small bowel was found at operation, 70% of those with an incorrect initial diagnosis (n = 23) required resection, as compared with 20% of those with a correct initial diagnosis (n = 10, P = 0.014, chi 2 with Yates' correction). Femoral hernias are frequently incorrectly diagnosed before hospital admission and this is associated with worsened outcome in urgent cases.