Evaluating feed efficiency of beef cattle has evolved from relying on single trait selection for increased gain to extensive use of multiple trait selection combining measures of gain and intake. Postweaning gain (difference between 365-d and 205-d age adjusted weights) is analyzed as part of National Cattle Evaluation programs and could be used in an index with shorter intake tests (currently >70d to accurately measure gain) to select animals for improved feed efficiency. Under this paradigm, producers could decrease costs per animal and increase genetic change by testing a greater number of animals per year. Objectives of this study were to compare 2 alternative indices for feed efficiency and to quantify the genetic response to selection for feed efficiency combining an intake test with PWG data. Strong genetic correlation estimates for steers and heifers between average daily gain (ADG) and postweaning gain (PWG) (0.81, 0.65) suggest PWG is a reliable proxy for ADG. On-test ADFI, on-test average daily gain ADG, and postweaning daily gain (PWG) records on 5,606 growing steers and heifers were obtained from the US Meat Animal Research Center in Clay Center, NE. Genetic (co)variances and EBV were estimated using a 6 trait animal mixed model with ADG, ADFI, and PWG as dependent variables for both steers and heifers. Indices combining EBVs for ADFI and ADG and for ADFI and PWG were evaluated. For each index, the weighting of gain was arbitrarily set to 1.0 and the weighting for ADFI was the negative of the average of the intra-contemporary group ratio of mean gain divided by mean ADFI. Values were combined with EBV to compute 2 index values per animal. Pearson correlations for steers (0.96) and heifers (0.45) indicated a strong relationship for steers between the indices. For steers, using the index with PWG rather than with ADG effectively results in the same genetic gain without additional intake records. Because more animals can be measured for intake, using PWG increases relative annual progress of selection for feed efficiency by 15%. These findings support using PWG data in combination with ADFI to determine efficient steers, lessen costs, and increase feed efficiency genetic change per year.