The objective of this research was to compare the adsorption and Fenton-adsorption treatments for the removal of contaminants in leachate from landfills and thus determine the most efficient one. The adsorption process with granular activated carbon was tested in two types of samples: raw leachate and leachate treated by Fenton. The results showed color, chemical oxygen demand (COD), total nitrogen and total organic carbon (TOC) removal rates higher than 99% through the Fenton-adsorption process, while total nitrogen, COD, color and TOC removal rates of 81, 89, 92 and 93%, respectively, were obtained through the adsorption process on the raw leachate. Gas chromatography coupled to mass spectrometry (GS-MS) was used to found that the main organic compound in the leachate produced in the landfill from Mérida city, Yucatán, Mexico, is bisphenol-A, which was removed only during the adsorption stage of the Fenton-adsorption process. Furthermore, the biodegradability index (BI) increased from 0.084 to 0.476 through adsorption and up to 0.82 through the Fenton-adsorption treatment.