Measurements of water vapor absorption coefficients for 27 CO2 laser lines are given. Some measurements were obtained using a spectrophone and others using a long path absorption cell. Measurements were made with pure water vapor, and with samples broadened with N2 and with O2-N2 mixtures. This is discussed in Section I and Tables II and IV summarize the results obtained. Studies of water vapor absorption by CO laser radiation were also conducted. This is discussed in Section II and the results are summarized in Table V. A new long path White cell was developed under this program. A brief description of this equipment is given in Section III. A small cw HFDF chemical laser also was developed. The results obtained are described in Section IV.