The association between bronchiectasis and human immunodeficiency virus infection, the resurgence of tuberculosis, especially in urban and immunocompromised patients, and the recognition of bronchiectasis as a manifestation of rejection in the transplant population are emerging clinical settings in which establishing the diagnosis of bronchiectasis is becoming increasingly important. High-resolution CT, by virtue of its well-established accuracy, is currently accepted as the optimal noninvasive means of diagnosing bronchiectasis. However, reliable diagnosis requires meticulous attention to technique and a thorough knowledge of potential pitfalls. These include, among others, respiratory and cardiac motion artifacts as well as effects of collimation and electronic windowing. It also is important to recognize diseases that may mimic the appearance of bronchiectasis as well as unusual manifestations of bronchiectasis that may obscure the diagnosis.