Abstract: A simultaneous class-selective extraction and analysis of 10 beta-blockers and beta-agonists from horse urine and wastewater using SuperIMIP SPE beta-receptor cartridges was demonstrated. One millimeter horse urine was centrifuged at 3000 g for 10 min, diluted with deionized water, and adjusted to pH 7 before loading on the cartridge. Ten millimeter wastewater was filtered with 1 ?m filter paper and adjusted to pH 6-7 before loading. Using SuperIMIP SPE protocol and LC-MS-MS conditions, lower quantitation limits ?0.1 ng/mL and 0.01 ng/mL were achieved for horse urine and wastewater respectively. Lower limits of detection for beta-blockers are estimated to be ?0.03 ng/mL fro urine and 0,003 ng/mL for wastewater