A total of 206 community-acquired and 73 nosocomial infections in 50 malnourished Jamaican children were studied prospectively. Predominant community-acquired infections in the 50 children, included gastroenteritis (68%), otitis media (60%), rhinopharyngitis (60%), oral candidiasis (46%), skin infections (40%), pneumonia (28%), bacteraemia (24%) and bacteriuria (18%). The most frequent nosocomial infections were rhinopharyngitis (34%), lower respiratory tract infections (24%) and septicaemia (18%). In those infections where an aetiological agent was identified, Giardia lamblia was the commonest enteric pathogen, Staphylococcus epidermidis, the most frequent blood culture isolate and Klebsiella sp. were recovered from the majority of urines. The lack of clinical signs and symptoms and atypical clinical presentation in some infected malnourished children were attributed to impairment of the acute inflammatory response. Diagnosis of infection in these children required a high index of suspicion and a comprehensive screening system. Nasal, throat and axilla swabs taken on admission revealed significant colonization with coliforms and pneumococcus; however, these swabs were not useful as indicators of potentially infective organisms. Four of the 50 children died and two of these deaths were attributed to infection.