Hospital activity of professionals who use ionizing radiation (IR) at work generates risks on their health. Good knowledge of radiation protection (RP) rules can contribute to minimize these risks. This descriptive and analytical study, carried out from March 25 to May 14, 2019 as a survey, focused on knowledge about IR and RP. It was intended for medical and paramedical staff from several departments of Ibn Rochd UHC in Casablanca. Among 135 surveyed workers, 83% with median age of 31 years (21 to 54 years) participated. 65.17% of participants were physicians whose 76% were in training. 47% of respondents had a high global level of knowledge, with mean score of 6.6/10. IR average score (7.8/10) were better than RP average score (6.23/10). The scores varied significantly according to RP education (p<0.002) and home department (p<0.002). RP score was more strongly correlated to RP education (η2=0.32) than to department membership (η2=0.14). Medical staff RP knowledge are insufficient. In order to improve workers’ knowledge on RP, and thereby protect their health, it would be desirable to set up systematic pre-hire training and continuing education programs as well as integrate a radiation safety officer into all departments operating under IR.