Purpose: The aim of the study is to do an investigation into students’ familiarity and use of online databases in Babol University of Medical Sciences.Methodology: The method applied is descriptive and data gathering tool is questionnaire. Using stratified random sampling, 340 persons were selected as sample of among research society. Finally, 305 questionnaires were analyzed. Collected data were analyzed by means of descriptive statistics and chi-square statistical test, and Spearman’s correlation coefficient. Also, software SPSS (version 16) was utilized.Findings: Research findings show that there is a significant relation between educational degree and familiarity of the students with online databases and also between educational filed and their familiarity with online databases; 34/8% of the students aren’t familiar with databases at all and also 42% of them don’t use of them at all; there is a significant relation between familiarity of the students with the databases and using of them; “ScienceDirect”, with 2/67% average of usage, is the most known and useful database; there is also a significant relation between access of students to the databases and their educational degree and discipline; access of the students to databases with 50/2% is average. And, about half of the students know Internet and Web-based information resources. It means that, there is a significant relation between familiarity of the students with databases and Internet.Conclusions: The most of the students (36/7%) indicated that familiarity with search techniques is as the most important factor for effective using of online databases.