In a 9-month study of acute lower respiratory infections (ALRI), the short-term prognostic implications of socio-economic and household risk factors were examined in 103 hospitalized pre-school Nigerian children. Seventy-nine (77%) subjects were potentially exposed to the combustion products of kerosene stoves, 16 (16%) to wood smoke and five (5%) to the products of cooking gas combustion. Only 17 subjects (17%) were exposed to household cigarette smoke. A highly significant association (p < 0.005) was shown between household cooking fuel and the outcome of hospitalization: five (63%) of the eight who died were potentially exposed to wood smoke. The duration of hospitalization was only significantly associated with paternal income (p < 0.05). None of the other domestic risk factors was significantly related to outcome or duration of admission. These findings suggest an association between an adverse outcome of ALRI and domestic exposure to wood smoke. While the hospital-based source will not allow definite conclusions, the present findings underscore the need for community-based studies. The implications for future strategies of ARI control are discussed, with suggestions.