The purpose of this study was to compare the lumbar lordotic angle (LL) and pelvic tilt angle (PT) in the simple modified Thomas test (SMTT) position with LL and PT in the Thomas test (TT) position. Participants (n = 20) were between the ages of 23 and 39 and had no history of trauma. LL and PT were measured by X-ray radiographs under three conditions: the SMTT position, TT position, and supine position. At the same time, the distance between the examination table and the popliteal fossa was measured with a ruler. These measurements were compared by one-way analysis of variance. LL (14.6 ± 6.7 degrees [°]) in the SMTT posi¬tion was significantly lower than in the TT position (18.6 ± 6.6 °) (p < 0.01). PT (33.5 ± 7.6 °) in the SMTT position was significantly higher than in the TT position (31.3 ± 6.9 °) (p < 0.05). The distance between the examination table and the popliteal fossa in the SMTT position (100 ± 37.7 mm) was significantly higher than in the TT position (73.5 ± 21A mm) (p < 0.01). These results suggest that LL and PT in the SMTT position are easier to assess than those in the TT position.