In disasters, health care providers need to find out the essential needs of the affected populations through Rapid Health Needs Assessment (RHNA). In East Azerbaijan earthquakes, a rapid assessment was performed by the provincial health system. The main purpose of this study was to explore the RHNA challenges. In this qualitative study (Grounded theory), data was collected through semi-structured interviews with purposely selected health care workers. The data collection process continued until data saturation. All interviews were recorded and then transcribed. The Colaizzi's descriptive method was used to analyze the data. The themes emerged from the analysis of the interviews were: 1) Logistic problems 2) Lack of RHNA tools 3) Inherent difficulty of RHNA in disaster situations 4) Lack of preparedness and 5) Lack of coordination between different organizations. These challenges result in inapplicable use of RHNA results. The most important challenge in this RHNA process was the lack of East Azerbaijan health center preparedness. Although they were familiar with the importance of RHNA, they did not have any plans for conducting RHNA.