This research aims to investigate the effect of guided inquiry learning model upon scientific attitude and science learning achievement which uses the posttest-only control group design. This research is conducted at the fourth grade students of SD Negeri in Kaliuntu. The research populations are 125 students and samples are 64 students. Data of scientific attitude was collected by using questionnaire method, and the data of science learning achievement was collected by using test method. The data was analyzed using SPSS 17.00 for windows based MANOVA. The results show that: (1) there are significant differences of scientific attitude and science learning achievement between student studying by using guided inquiry learning model and conventional learning model (F=29.110;p<0,05), (2) there is significant difference of scientific attitude between student studying by using guided inquiry learning model and conventional learning model (F=22.649;p<0.05), (3) there is significant difference of science learning achievement between student studying by using guided inquiry learning model and conventional learning model (F=39.144;p<0.05).