Background and objective: Low quality of piped water in Behbahan city and lack of portability of water is the reason of using water desalination systems at homes. Knowledge and attitude have a direct effect on the people’s performance in using thesedevices. Therefore in this study, knowledge, attitude and performance of people in Behbahan city regarding using water desalination devices at home has been investigated. Methods: This is a cross-sectional analytic study conducted in 2015. The study population was all families who were using water desalination devices at home in Behbahan city. Based on the calculations, 172 people were selected randomly to participate in the study. The data collection tool was a researcher made valid and reliable questionnaire (a=0.76). The questionnaire included 4 parts (personal information and questions to measure knowledge, attitude and performance) and was completed by participants. The collected data were analyzed by SPSS 16, using ANOVA, independent T-test and Pearson correlation coefficient test at the confidence level of P