Of the four important skills in any second language pedagogy, reading comprehension is of paramount importance for students in the Iranian universities. A decision was therefore made to check the students' skill and ability in reading comprehension on the basis of 'semantic mapping' task inYazd Shahid Sadoughi University of Medical Sciences. In this quasi-experimental study, six general-English classes in Shahid Sadoughi University were assigned randomly to 3 control and 3 experimental groups. Students were studying in Family Health, Environmental Health, and Nursing fields. A pretest and posttest was held and the students were compared both at the beginning and at the end of the study. Data were then analyzed through ANOVA and paired-test via SPSS software. The findings revealed no statistically significant relationship between the two techniques. However, 'semantic mapping' technique, in terms of the mean score, proved more effective for Nursing students (M=6.25) compared with the students of Environmental Health (M=2.60) and Family Health (M=4.62). The results of this study are in line with a similar study carried out with medical and dental students (2006) in which the semantic mapping group enjoyed significantly higher reading comprehension ability than the relevant control group at the end of the study. (Note that the Nursing students in Iranian universities have a better position compared with Health-group students but a lower position compared with Medical and Dental students) This study suggests that the higher proficiency level of the learners is the more they may benefit from semantic mapping technique as a while-reading activity.