Field-trapped tsetse Glossina pallidipes, G. brevipalpis and G. austeni were dissected and the incidence of hypertrophy of the salivary glands (HSG) recorded. This condition was observed only in G. pallidipes. The highest level of infection (15.6%) was observed in July in one of the trapping sites. Both very young teneral (ovarian category 0a) and very old (ovarian category 7 + 4N) tsetse had greatly enlarged glands. The differences in bi-monthly HSG incidence for the five trapping sites were statistically significant. The level of infection in males and females did not show significant differences.