This study investigates the effects of Concept Mapping-Guided Discovery Integrated Teaching Approach on the achievement and retention of chemistry students. The sample comprised 162 Senior Secondary two (SS 2) students drawn from two Science Schools in Nasarawa State, Central Nigeria with equivalent mean scores of 9.68 and 9.49 in their pre-test. Five instruments were developed, validated and used by the investigator for the study; they are namely; Chemistry Achievement Pre-Test (CAPE), Chemistry Achievement Post-Test (CAPO), Chemistry Achievement Retention Test (CART), Lesson Plans for the Control Group (LPCG) and the Lesson Plan for the Experimental Group (LPEG). Pre-test / post-test control group design was employed. Results of the Scheffe's test for multiple comparisons revealed that boys in the experimental group performed better than girls in the experimental group. The results of the t-test analysis of the retention test showed that the mean score of the experimental group was significantly better than that of the control group (p<0.05). It is strongly recommended that chemistry teachers should be encouraged to adopt this method for teaching difficult concepts.