This study investigated journalists’ awareness and knowledge of Freedom of Information Act (FOIA), the extent to which Nigerian journalists use the FOIA, constraints to the use of FOIA in investigative reporting and how journalists perceived the influence of the Act on investigative reporting in Nigeria. Survey method was used to elicit information from the purposively and conveniently sampled study population comprising journalists in print media outfits in Lagos. Questionnaires were used to collect data from 240 respondents of which 182 (138 respondents from newspaper and 44 respondents from magazine outfits) were valid. Data were analyzed using simple frequency and non- parametric chi-square tests with the aid of Statistical Package for Social Science (SPSS 17.0). Results were presented in simple percentages and frequency count tables. Findings reveal that Nigerian journalists hardly use the FOIA for investigative reporting though they are aware and perceived it as beneficial. It also revealed that FOIA did not make any significant input into investigative reporting in Nigeria due to certain constraints. Nonetheless, the study recommended that certain grey areas of FOIA need to be reviewed for ease of access. Media outfits need to train journalists on the use of FOIA and government needs to be sincere with implementation of FOIA by training/enlightening public servants. Government also needs to prosecute corrupt public officials and ensures computerization of public records for timely access to requested information.