Fast methods using balanced steady-state free precession have been developed to reduce the scan time of T1 and T2 mapping. However, flip angle (FA) profiles created by the short radiofrequency pulses used in steady-state free precession deviate substantially from the ideal rectangular profile, causing T1 and T2 mapping errors. The purpose of this study was to develop a FA profile correction for T1 and T2 mapping with Look-Locker 2D inversion recovery steady-state free precession and to validate this method using 2D spin echo as a reference standard. Phantom studies showed consistent improvement in T1 and T2 accuracy using profile correction at multiple FAs. Over six human calves, profile correction provided muscle T1 estimates with mean error ranging from excellent (−0.6%) at repetition time/FA = 18 ms/60° to acceptable (6.8%) at repetition time/FA = 4.9 ms/30°, while muscle T2 estimates were less accurate with mean errors of 31.2% and 47.9%, respectively. Magn Reson Med, 2012. © 2012 Wiley Periodicals, Inc.