This study was conducted in order to determine the differences in integrated scientific process skills (designing experiments, forming data tables, drawing graphs, graph interpretation, determining the variables and hypothesizing, changing and controlling variables) of students (n = 17) who were taught with an approach based on scientific argumentation and of students (n = 17) who were taught with a traditional teaching approach in Grade 11 chemistry. The study was conducted at a high school in Çankiri, Turkey. A multiformat Scientific Process Skills Scale was administered to both groups as a pre- and posttest; it contained 29 items in 5 modules and consisted of limited and unlimited open-ended, multiple-choice, and paper-pencil performance assessment questions. Repeated t-test and analysis of variance (MANCOVA) were applied to analyze the data. It was found that the integrated scientific process skills of students in both groups improved significantly except skills of "forming a data table" and "graphic interpretation skills" for group. MANCOVA results revealed that there was a statistically significant difference between the groups on the combination of 5 dependent variables. The teaching approach had a significant effect on integrated scientific process skills except for the designing experiments skills. In sum, the scientific argumentation-based teaching approach was more effective in acquiring science process skills than the traditional teaching approach.