In-service training has been used as a certain procedure for improving service quality and developing staff knowledge and awareness. This study aimed to evaluate the in-service training climate in libraries located in northern Iran medical universities from their staff viewpoints with ClimateQual survey tool. As a cross-sectional and analytical-survey, this study conducted among all staff of northern Iran medical libraries –including Babol, Mazandaran (Sari), Golestan (Gorgan) and Gilan (Rasht)- in 2012. The research instrument included ClimateQual Questionnaire developed by Association of Research Libraries (ARL) in 2009 and normalized by the researcher in his PhD dissertation in 2011. The rank of in-service component among all 9 components of ClimateQual was 8 (10.24 ± 3.17). As result, in-service training climate was not satisfactory from the staff viewpoints. ANOVA test results showed that in-service status was somewhat similar quantitatively and qualitatively in the studied universities (Sig.=591). There was a significant difference between staff in-service training mean scores according to their educational degrees (Sig.= 0.006). It is necessary to revise deeply in the quality and quantity of staff inservice training in the studied libraries.