A prospective study was done on 1,699 patients operated upon for appendicitis to correlate the operative diagnosis of the surgeon and the histopathologic diagnosis of the pathologist. There are surgeons who only send the appendices for histopathologic study when the operative findings are inconclusive and surgeons who invert rather than resect the appendices on finding a grossly normal appendix at operation. This study was done to find out whether or not these practices of leaving some of the appendix unexamined histopathologically are clinically safe. In this study, surgeons missed abnormal pathologic findings in the appendix in ten of 13 patients and this is irrespective of whether the appendix was normal, acutely inflamed, gangrenous or perforated. The majority of these lesions either require further investigation, treatment or they affected the prognosis of the patient. Nineteen per cent of the patients diagnosed as having normal appendices grossly were found to have acute appendicitis and 7.7 per cent diagnosed as acute appendicitis were normal. Based upon these data, we conclude that the operative diagnosis of the surgeon cannot be relied on to detect abnormal pathologic findings in the appendix. Additional important clinical information can be gained by routine histopathologic study of the resected specimens, and inversion of the appendix is clinically not safe.