Background: Iran experienced a big jump in higher education in 1990s In compatible with this jump the number of PhD students was increased considerably particularly those who were sponsored to study abroad It is incredibly important to explore the issues around the study of these students which its findings can be used for further planning Objective: To assess the education duration of Iranian PhD students graduated from universities in UK and Irland between 1995 and 2001 Also to compare the durations of studies of students in medical fields with that in other students Methods: The data of Iranian PhD students were collected from the Deputy of Science in the Embassy of Iran in UK In order to minimize the selection bias introducted by sensored data only the information of students who started their studies before 1997 was analysed Results: Around 30% of students were sponsored by the Health Ministry of Iran to study in medical fields In average the durations of studies in students of medical fields was not statistically different with the durations in other students (425 months versus 42 months respectively p=023) Less than 15% of students finished their studies within 3 years however it was around 10% greater in students of medical fields The diversity of the durations of studies was greater in medical field students The correlation coefficients between the duration of studies and age the number of children and English score of students in the beginning of their courses were 01 002 and 017 respectively the last two coefficients were not statistically significant In addition the students in large cities and in small towns finished their courses more or less with the same length  Conclusion: Most of students could not finish their studies within three years which is the duration of scholarship in Iran therefore it is suggested that the system revises its regulations In addition it is suggested that the scholarship system chooses younger students because age had a positive association with the length of study