In this work, a comparison between different agave fiber surface treatments has been presented to improve the mechanical properties of rotomolded natural fiber composites (NFC). The fiber treatments were carried out with sodium hydroxide, 2-chlorobenzaldehyde, maleic anhydride grafted polyethylene, acrylic acid, methyl methacrylate, and triethoxy vinyl silane. In particular, a simple dry-blending technique was used to introduce agave fibers in the polymer matrix (linear medium density polyethylene). The samples were produced at 15 wt% fiber content and characterized in terms of morphology, density, hardness, and mechanical properties (tension, flexural, and impact). The results showed that surface treatments improved the homogeneity (uniform morphology) of NFC and the best mechanical improvements (77% for strength and 30% for stiffness) were obtained with maleic anhydride grafted polyethylene. (C) 2016 Society of Plastics Engineers