The aim of the study was to estimate the value of CT in the diagnosis of abdominal wall hernias and at the same time to create a standard for this CT investigation. Twenty-four patients with suspected hernia of the abdominal wall were examined. All were operated on. The CT scans were assessed by two radiologists to estimate the interobserver variation. The CT diagnoses made by the two radiologists were correct in 83 % and 79 % of cases, respectively. The sensitivity was 0.83 in both CT evaluations and the specificity was 0.83 and 0.67, respectively. The predictive value of a positive CT finding was 0.94 and 0.88, while the predictive value of a negative CT finding was 0.63 and 0.57, respectively. The interobserver variation (kappa) was 0.87. The study therefore indicates that a positive CT finding of abdominal wall hernia is reliable, while a negative finding does not exclude the diagnosis. The interobserver variation of the CT diagnoses is acceptable. To achieve the highest diagnostic accuracy, it is recommended to always use the Valsalva manoeuvre, oral intake of contrast and 10/10 mm CT slices.