The intent of this study is to develop a predictive model to convert an oxygen desaturation index (ODI) to an apnea–hypopnea index (AHI). This model will then be compared to actual AHI to determine its precision. One thousand four hundred and sixty-seven subjects given polysomnograms with concurrent pulse oximetry between April 14, 2010, and February 7, 2012, were divided into model development () and verification groups () in order to develop a predictive model of AHI using ODI. Quadratic regression was used for model development. The coefficient of determination () between the actual AHI and the predicted AHI (PredAHI) was 0.80 (), which was significant at a . The areas under the receiver operating characteristic curve ranged from 0.96 for AHI thresholds of and to 0.97 for thresholds of and . The algorithm described in this paper provides a convenient and accurate way to convert ODI to a predicted AHI. This tool makes it easier for clinicians to understand oximetry data in the context of traditional measures of sleep apnea.