Chronic, recurrent disease involving the alimentary tract, joints, skin and peripheral lymph nodes, central nervous system and conjunctivae was recorded over a 229 day period in a young Weimaraner dog, first presented at 15 weeks of age. The dog had a left shift neutrophilia during periods of active disease and persistently subnormal levels of serum immunoglobulin G (IgG; 2.8 to 9.2 mg/ml) and IgA (< 0.1 to 0.26 mg/ml) in the absence of circulating immune complexes. One littermate died suddenly at 27 weeks of age and a second littermate had an episode of pyoderma. Both of these dogs had low serum IgG (3.5 to 7.2 mg/ml) and the second littermate also had reduced serum IgA (< 0.1 to 0.15 mg/ml). The dam of the litter and three other related dogs had reduced serum IgA (0.22 to 0.31 mg/ml); circulating immune complexes were not recorded in any of the related dogs. This case is the first of putative immunodeficiency of Weimaraners in the UK. Inability to synthesise adequate concentrations of serum immunoglobulins should be considered a primary defect in this disorder.