The SMP buffer test is commonly used in PA and the U.S. to determine the lime requirement (LR) of acid soils. The buffer solution contains potassium chromate, a carcinogen, and all waste must be collected for disposal in a hazardous waste facility. An alternative to the SMP buffer is the Mehlich buffer. Although the Mehlich buffer contains barium chloride (BaCl2), a regulated compound, calcium chloride (CaCl2) has been shown to be an effective substitute. The goal of this study was to compare the SMP buffer and the modified Mehlich buffer for estimating LR on PA soils and determine if the modified Mehlich buffer could provide an effective alternative to the SMP test. Twenty-two agriculturally important, PA soils with pH values ranging from 4.5 to 6.4 were collected. Soils were air-dried, sieved, and tested for SMP and modified Mehlich buffer pH. The actual LR of each soil was determined by incubating soils for 3 months with calcium carbonate at rates of 0, 1/3, 2/3, 1, 1 1/3 and 2 times the estimated LR from the SMP test. The actual LR was compared with the modified Mehlich and SMP buffer pH values to determine which test most effectively estimated LR. The modified Mehlich buffer was shown to be a better predictor of the lime required to raise soils to either pH 6.5 (r2 = 0.92) or 7.0 (r2 = 0.87) in comparison to the SMP buffer (r2 = 0.87 and 0.82, respectively).