In 100 healthy children under the age of 3 years living in the vicinity of Goroka, Papua New Guinea, the nares were cultured for Haemophilus influenzae type b (Hib), and a urine sample was obtained for measurement of Hib polysaccharide (PS) by ELISA. Hib carriage was detected in nine children and Hib PS was detected in the urine of 11. Hib PS was found in seven of nine Hib nasal carriers compared with four of 91 healthy children without Hib in their nares (p < 0.001). The range of urine antigen concentrations in the two groups was similar (0.6 to 2.7 ng/ml). The relative risk of antigenuria in the carriers, compared with the children with negative nares cultures, was 58 (95% confidence interval, 10.5-324). These data extend previous observations from Hib carriers studied in the United States and show that Hib carriage in children from a developing country is associated with antigenuria. Further studies are needed to determine whether carriers and patients can be differentiated by differences in the magnitude of the concentration of Hib PS excreted in urine.