The present paper addresses the critical absence of documented hydroseeding results from tropical alpine environs, reporting the results of a hydroseed slurry field experiment at 3900 masl on a reconstructed geostabilized slope at the Yanacocha mining lease in the Northern Peruvian Andes. The field experiment was urgently required to improve the results of ongoing hydroseed revegetation activities, which had failed to provide adequate cover for erosion control under the unique tropical alpine climate and acidic soil conditions. The performance of the original hydroseed slurry and three new slurries were systematically evaluated over a 14-month period. The main differences in slurry composition included organic, synthetic and cementitious binders, lime-based soil amendments, seed and amendment quantities and organic compost additions, as well as slight changes to several other components. The slurry treatments were evaluated by resulting vegetative cover, with additional observations of soil and foliar nutrients and aboveground mass measurements taken to assist cover interpretations. Two of the new slurries produced the significantly higher and different vegetative cover. One slurry (Plot C) rapidly (within two months) attained and maintained ~100% cover, while the other (Plot D) attained ~50% cover by the end of the 14-month period, the latter still being a significant improvement on the original slurry (11%). These same two treatments showed indications of improved soil conditions, as well as biomass-necromass ratios similar to the native vegetation, although the foliar micronutrient content of all treatment samples were half that of the native vegetation. While individual component effects were not tested, increased seed quantity, soil amendments and compost addition appeared to be responsible for increased cover. The Plot D slurry provided the most cost effective vegetative cover, although the real cost effectiveness (considering remediation activities to compensate for incomplete cover) led to the mine management immediately employing the successful slurry tested in Plot C, which to date continues to provide highly improved hydroseeding results. The results indicate that further trials in tropical alpine environs should specifically test seed quantities, soil amendments and composts. The documentation and follow-up of ongoing hydroseed activities should be encouraged through commercial and academic collaborations, in order to fast track the improvement of tropical alpine hydroseeding activities and eventually facilitate the incorporation of native species. Copyright © (2010) by the International Erosion Control Association.