The International Journal Of Science & Technoledge 2017, Vol 5(10)Educational studies in the area of motivation have led to the conclusion that learners with a high sense of self-concept tend to approach school related tasks with confidence and that success in those tasks reinforced their self-confidence. The major aim of this study was to compare the effectiveness of an inquiry-based approach and conventional teaching in the development of students’ self-concept towards practical laboratory experimentation. The study used genetic as the case study to find out whether or not these two styles of teaching genetics would develop differently students’ perceived selfconcept towards science experimentation. Inquiry-based approaches to science have been heavily emphasized by the newly adopted curriculum policy in Tanzania. Two months (08weeks) of February and March 2015 were spent in teaching themes within genetics at the selected schools in Morogoro Municipality using two different methods. These genetics lessons were not designed specifically to contribute to students’ self-concept towards scientific experimentation. Yet, it was assumed that it might have a positive effect on the student attitudes. The study employed a quasi-experimental research design with pre and posttests. The FSWEx self-concept scale by Damerau (2012) was used as a data collection tool. The questionnaire measures students’ self-concept in three subscales of experimentation namely planning of experiments, actual experimenting and analyzing data. Although it was conceptualized that the experimental group would develop higher positive self-concept towards experimentation in science than the control group, this was not the case in this study. No statistically significant difference was found on students the development self-concept posttest scores in all three subscales based on the type of instruction they received when null hypothesis was subjected to independent samples t-test. However, the linear model with repeated measures found that regardless of the method of teaching, there were significant gains in the self-concept of students towards scientific experimentation overtime.