Background & Objective: Education is one of the most basic necessities of human communities and an important base of continuous development Variation in teaching methods is an obvious need in our complicated world and selecting the most appropriate teaching method is the key issue at every stage of learning process The aim of this study was to compare the efficacy of two teaching methods of group discussion and lecturing on the learning rate of the students of Laboratory Medicine in Medical Parasitology and Mycology course in Yazd Shahid Sadoughi University of Medical Sciences and Health Services during the academic year of 2005006 Methods: This semiexperiential study carried out on 50 students of Laboratory Medicine selected by purposive sampling method The students divided into two groups matched for age sex and average scores of their last two semesters One group was taught by using group discussion method and the other group by the traditional lecturing method for 8 sessions each lasting 30 minutes Data collection was done by a questionnaire including demographic information and 50 questions of Medical Parasitology and Mycology given to the subject as class quizzes midterm exam final exam and a test one month after the instruction sessions (25 questions were on taxonomy I 15 ones on taxonomy II and 10 questions on taxonomy III) Results: From 50 students 30 ones (60%) were female and 20 ones (40%) were male According to the findings both methods increased the level of knowledge significantly but this increase was more in discussion group comparing to the lecture group (P=0/002 and P=0/003) Conclusion: The research findings show a higher rate of learning for group discussion method that is due to the more efficacy of this method in promoting intergroup relations brainstorming groupactivity group assimilation and elevating level of judgment and analytic ability Therefore this teaching method is suggested especially for teaching Medical Parasitology and Mycology