Thirty-four species of tropical plants found in Puerto Rico were considered for possible use as high protein green leaf vegetables and as sources of leaf protein concentrate. They were tested for protein and carotenoid contents, and for toxins, including alkaloids, hydrocyanic glucosides, and oxalic acid. Six species (Manihot esculenta, Sauropus androgynous, Cnidoscolus chayamansa, Canavalia ensiformis, Lablab niger, and Vigna unguiculata)that combine high protein yields with suitable agronomic characteristics were selected for further trials and were described Green leaves are concluded to be crops of high potential for Puerto Rico and the protein-hungry tropics.Se estudio la posibilidad de usar como fuentes de proteína 34 especies de plantas tropicales ricas en proteínas que se encuentran en Puerto Rico. También se determinaron sus contenidos de carotenoides y la presencia de venenos como glucosidos de ácido prúsico, alcaloides y ácido oxálico. Seis de estas especies que combinan riqueza proteica y características agronómicas deseables se seleccionaron y se describen. Estas se estudiaron más extensamente y se consideran de elevado potencial proteico no solo para Puerto Rico sino para el mundo tropical.