Background HIV testing of women in child bearing age is an entry point for preventing mother-to-child transmission of HIV (MTCT). This study aims to identify the proportion of women tested for HIV and to determine factors associated with utilization of HIV testing services among pregnant mothers in primary care settings in northern Ethiopia. Methods A cross sectional study was conducted in 416 pregnant women from four primary care centers between October 2, 2012 and May 31, 2013 in East Gojjam, Ethiopia. Results The proportion of mothers who tested for HIV was 277(67%). Among mothers who were not tested for HIV, lack of HIV risk perception (n = 68, 49%) was a major self-reported barrier for HIV testing. A multivariable logistic regression analysis showed that those pregnant women who had comprehensive knowledge about MTCT had an Adjusted Odd Ratio (AOR) of 3.73 (95% CI: 1.56, 8.94), having comprehensive knowledge on prevention of mother to child transmission (PMTCT) of HIV an AOR of 2.56 (95% CI: 1.26, 5.19), and a favorable attitude towards persons living with HIV an AOR of 2.42 (95%CI, 1.20, 4.86) were more likely to be tested for HIV. Conclusion One third of pregnant women had never been tested for HIV until the time of the study. Efforts should be made to improve mother’s knowledge about MTCT and PMTCT to increase uptake of HIV testing. Enhancing mother’s HIV risk perception to scale up HIV testing in resource limited setting is highly recommended. Electronic supplementary material The online version of this article (doi:10.1186/s12884-017-1389-2) contains supplementary material, which is available to authorized users.