Evaluating user satisfaction is one of the methods to ensure the usability of information systems. Considering the importance of nursing information systems in patient health, the objective of this study is to evaluate nurses' satisfaction with two widely used nursing information systems (Peyvand Dadeh and Tirazhe) in Iran. This descriptive-analytical study was done on 230 nurses in all teaching hospitals of Kerman University of Medical Sciences in 2015. Data were collected using an augmented version of a questionnaire developed by IBM. Data were analyzed by SPSS.16 using descriptive and analytical statistical methods including t test, analysis of variance, and Pearson correlation coefficient. The mean of overall satisfaction with the two systems was 61 ± 2.2 and 74 ± 2.4, respectively. The mean of satisfaction with different systems dimensions, that is, ease of use, information quality, and interface quality, was, respectively, 24 ± 1.9, 26 ± 9.7, and 12 ± 4.7 for Tirazhe and 29 ± 1.1, 39 ± 1.04 and 13 ± 5.3 for Peyvand Dadeh system. Nurses' satisfaction with both systems was at a medium level. The majority of nurses were relatively satisfied with the information quality and user interface quality of these systems. The results suggest that designing nursing information systems in accordance with their users' need improves usability. Hence, policy and decision makers of healthcare institutions should invest on usability when purchasing such systems.