Precipitation drives the water cycle and plays a significant role in the atmospheric circulation. Several precipitation datasets have been developed to meet the need for a wide range of applications including drought analysis and identification, flood prediction and protection, hydrological modeling, water resources management, agriculture, and urban planning, to name but a few. Despite a broad range of investigations, no specific type of precipitation dataset has been considered as the most valid one in all regions. In this study, the performance of 44 global precipitation datasets has been assessed over Iran at daily and monthly time scale. To this end we have employed a dense network of ground observations and various evaluation approach and metrics. Our results rank datasets over 30 major basins of Iran for the two categories of best long-term and best (Near) Real Time (RT). The findings of the study can be beneficial for the dataset developers and hydro-atmospheric modelers.