The computed tomography (CT) scans of 37 patients with primary hypogammaglobulinaemia were reviewed to determine the frequency of enlarged mediastinal lymph nodes and splenomegaly in this group. None of the 10 X-linked Agammaglobulinaemia (XLA) patients had enlarged nodes and only one had splenomegaly. Eleven of the 27 Common Variable Immunodeficiency (CVID) group had enlarged nodes (41%) and 13 had splenomegaly (48%). There was no significant correlation between the presence of enlarged nodes and splenic enlargement. Twenty-two patients had bronchiectasis but the presence of bronchiectasis did not correlate with the presence of either splenomegaly or lymphadenopathy. Three to 6 years follow-up is available for 36 of the 37 patients and none of this group have developed lymphoma or other malignancy. Enlarged mediastinal nodes and/or splenomegaly are frequently found in patients with CVID and are usually due to a benign, non-neoplastic, process. Mediastinal lymph node enlargement is not a feature of XLA and splenomegaly is unusual in this condition.