This study investigated the relative contributions of individual, institutional and system factors to utilisation of Research4Life databases by scientists in the National Agricultural Research Institutes (NARIs) in Nigeria. The study adopted the descriptive survey research design of the correlational type. Simple and stratified random sampling techniques were used to select 744 (62%) research scientists from a population of 1,205 in 13 NARIs. A validated and pre-tested questionnaire was the instrument adopted for this study and it consisted of 105 questions arranged in five sections A – E with 0.99 reliability coefficient based on Cronbach alpha method. Descriptive and inferential statistics - simple percentage, mean, correlation, multiple regression and analysis of variance were used to analyse the data. Result revealed that utilisation of Research4Life databases was low and the 22 individual, institutional and system factors significantly influenced utilisation of Research4Life databases in the NARIs. Individual, institutional and system factors showed varied levels of variances to utilisation of Research4Life databases in the NARIs. Out of the 22 factors investigated, five factors made significant relative contributions towards utilisation of Research4Life databases in the NARIs. System factors made significant relative contributions of three factors (perceived ease of use, database design features, local journal content), followed by one institutional (accessibility of databases) factor and one individual factor (computer anxiety). For increased utilisation of Research4Life databases in NARIs in Nigeria, individual, institutional and system factors have to be given utmost consideration.Keywords: individual factor, institutional factor, system factors, utilisation, Research4Life databases, Agricultural scientists