esults obtained from the S3-1 ionization gauge measurements are statistically examined for hemispheric asymmetries in neutral density behavior. The parameter analyzed in this study is the mean value R, the ratio of the measured density to the Jacchia 71 model value. Over 150,000 values obtained during the period from November 1974 to May 1975 and covering the altitude range from perigee (about 160 km) to 300 km are considered. Results are presented in the form of frequency histograms and graphs of mean ratios vs latitude. Significant hemispherical asymmetries are found and described in detail.