This study investigated the Taiwanese students' swimming ability in junior high schools that had swimming pools, and compared the percentages about the students' swimming ability in different sexes and in different areas. The subjects were 29 schools selected and evaluated on site by two experts. There were 10,979 students (males=5,563, females=5,416) evaluated. The instrument of this study was a recording table developed by the author to record students' swimming ability. Data were analyzed by descriptive statistics, paired t-test and one-way ANOVA. The results showed that (1) the students' who passed the test of 25 meters was 39.8%, (2) more male than female students passed the test, and (3) the central area in Taiwan had the lowest percentage of students who passed the test.