Accurately estimating Lime Requirements (LR) of acidic soils has been a concern since liming practices began. The objectives of this study were to 1) determine if the SMP buffer is accurately predicting LR of Kansas soils, 2) re-calibrate the SMP and Mehlich buffer to accurately estimate LR of Kansas soils to specific target pH values, and 3) compare the effectiveness of the 60-d incubations in determining LR versus field observed lime response. Ninety-seven soil samples received by the Kansas State University (KSU) Soil Testing Laboratory during 2004 were used in this study. Samples represented soils from eastern and central Kansas with 1:1 soil pH < 6.5. Samples collected were used to evaluate the current LR based on the SMP buffer and to re-calibrate the SMP buffer, Mehlich buffer, and Ca(OH)2 titration to Kansas soils. Sixty day greenhouse incubations with a varying amount of CaCO3 was used to determine the actual LR of each soil. Slope values < 1 and Y-intercepts > 0 indicated that the SMP either overestimated LR at low values or underestimated LR at relatively high LR values for target pH of 5.5, 6.0, and 6.8 compared to 60-d incubations with CaCO3. Calibration of the Mehlich buffer to a target pH of 6.8 provided a better fit compared with the SMP buffer. Titration with 0.022 M Ca(OH)2 resulted in a LR (to a target pH of 6.8) 45% less that measured by the 60-d incubation. Evaluation of the three LR methods on twelve soils indicated LR estimated by the Mehlich buffer was not significantly different compared with the LR from the 60-d incubation. Recalibration of the SMP with soils from Kansas did not drastically improve estimation of LR compared to 60-d incubations. However, LR was improved when LRs were < 4.5 Mg/ha. Comparison of LR from 60-d incubations with field-observed lime response showed that LR of field sites was 2 to 3 times greater than that of the 60-d incubation.