We report the results of an accurate measurement of the optical oscillator strengths of the prominent resonance lines of He, Ne, Ar, and Kr in the vacuum-ultraviolet region based on the absorption of resonance radiation. The transmission of this radiation through a layer of gas of finite thickness is measured as a function of the number density of the gas. The transmission function is fitted to this data to obtain the absorption oscillator strength. The accuracy of the present measurements ranges from 2.5% to 4%. The results are as follows: He i (58.4 nm), 0.2683±0.0075 (2.8%); He i (5.37 nm), 0.0717±0.0024 (3.4%); Ne i (74.4 nm), 0.010 17±0.000 30 (2.9%); Ne i (73.6 nm), 0.1369±0.0035 (2.6%); Ar i (106.7 nm), 0.0616±0.0021 (3.4%); Ar i (104.8 nm), 0.2297±0.0093 (4.0%); Kr i (123.6 nm), 0.1751±0.0049 (2.8%); Kr i (116.5 nm), 0.1496±0.0038 (2.5%).