During a period of 5 years, 42 cases of invasive Haemophilus influenzae type b (Hib) disease were studied. An outstanding finding in our patients was occult bacteraemia, which was detected in 13 (31 per cent) patients. Other clinical conditions encountered were nine (21 per cent) patients with pneumonia, nine (21 per cent) with meningitis, six (14 per cent) with cellulitis, three (7 per cent) with arthritis, one (2 per cent) with epiglottitis, and one (2 per cent) with urinary tract infection. The mean age of children was 21 months (range 1-156 months); the majority (62 per cent) belonged to the age group 7-18 months. There were 24 females and 18 males. Eighty-one per cent of these patients were Saudi nationals. Five isolates (12 per cent) of Hib were resistant to ampicillin and similar numbers were resistant to chlorampenicol. Twenty-five children (60 per cent) were treated with ampicillin, nine (21 per cent) with chlorampenicol and eight (19 per cent) with ceftriaxone. All patients made complete recovery.