BACKGROUND: Since 1990, 500000 people have fled from Liberia and Sierra Leone to Guinea, west Africa, where the government allowed them to settle freely, and provided medical assistance. We assessed whether the host population gained better access to hospital care during 1988-96. METHODS: In Guéckédou prefecture, we used data on major obstetric interventions performed in the district hospital between January, 1988, and August, 1996, and estimated the expected number of births to calculate the rate of major obstetric interventions for the host population. We calculated rates for 1988-90, 1991-93, and 1994-96 for three rural areas with different numbers of refugees. FINDINGS: Rates of major obstetric interventions for the host population increased from 0.03% (95% CI 0-0.09) to 1.06% (0.74-1.38) in the area with high numbers of refugees, from 0.34% (0.22-0.45) to 0.92% (0.74-1.11) in the area with medium numbers, and from 0.07% (0-0.17) to 0.27% (0.08-0.46) in the area with low numbers. The rate ratio over time was 4.35 (2.64-7.15), 1.70 (1.40-2.07), and 1.94 (0.97-3.87) for these areas, respectively. The rates of major obstetric interventions increased significantly more in the area with high numbers of refugees than in the other two areas. INTERPRETATION: In areas with high numbers of refugees, the refugee-assistance programme improved the health system and transport infrastructure. The presence of refugees also led to economic changes and a "refugee-induced demand". The non-directive refugee policy in Guinea made such changes possible and may be a cost-effective alternative to camps.