This research aims to evaluate the effectiveness of teaching and learning tools based on the guided inquiry approach. The guided inquiry approach is expected to be able to facilitate students to be active in exploring knowledge by using science process skills and to be scientific as the natural science learning process should be. The research design used is the Tessmer development design. The data analysis technique is quantitative descriptive. The research sample were 8th Grades students of SMPN 9 Banjarmasin and SMPN 23 Banjarmasin. The research subjects consisted of 2 experimental classes each with 30 and 25 students and 1 control class consisting of 30 students. The results showed effective learning tools to improve science process skills and scientific attitudes based on: 1) Student learning outcomes in the experimental class have exceeded classical completeness; 2) The science process skills of indicators observing, classifying, predicting, interpreting and communicating in both experimental classes are good and very good. N-gain scores in both classes of experiments are quite effective. ANCOVA results show that 78% of the learning tools developed are able to provide a better influence on the science process skills of experimental class students; 3) Completeness of indicators of scientific attitudes of curiosity, thorough and responsible categorized both in the two classes of experiments. Individual completeness in both experimental classes exceeded 75%, which means that classical completeness was achieved.