Tests of ventilatory function including pulmonary diffusing capacity were made in 18, the last period pregnant women and 20 non pregnant women. During the study was from May 22 to June 4, the subject of study refered 38 women (20 student and the staff of Physical Therapy at Masan college and 18 women who were examined at Masan OO obstetrics Hospital). All the studied subjects had no clinical abnormalities of the cardiorespiratory system. Mean FVC and FEV1.0 were significantly decreased in the last pregnant women compare with that of non pregnant women. All the Other Measurements were not differ from those of non pregnant women. The results of this study were as follows. l. Pregnancy was associated with decrease in mean FVC and FEVl.0, Which at the last period pregnant women were $2.70{pm}0.58{iota},;2.31{pm}0.53{iota}$ below the non pregnant women mean $3.03{pm}0.33,;2.64{pm}0.44{iota}$ : Both changes were statistically significant.(P<0.05) 2. The mean VC, which at the last period pregnant women was $3.15{pm}0.45{iota}$ below the non pregnant women mean $3.28{pm}0.33{iota}$ and the mean IC $2.21{pm}0.53{iota}$ below the non pregnant women mean $2.22{pm}0.54{iota}$, but the difference were not statistically significant. 3. The mean ERV, IRV were not statistically significant between non pregnant women and pregnant women. 4. The mean TV were not statistically significant between non pregnant women and pregnant women. 5. The mean FEVl.0(G) were not statistically significant between non pregnant women and pregnant women.