The main purpose of this PhD research project was a critical taxonomic investigation of Basidiomycetes of District Mansehra, Pakistan. The collection was made from 30 different sampling sites of the District through consecutive visits both in the rainy and dry seasons of the years 2009 to 2011. During the course of this exploration a large no of specimens were collected out of which 101 taxa belonging to 41 genera of Basidiomycota were identified on the basis of morphological and anatomical traits, among these 13 taxa viz. Amanita hemibapha subsp. hemibapha, A. oblongospora, A. ohgiensis nom. prov., Hymenopellis luteus nom. prov, Lactarius pterosporus, Macrolepiota dolichaula, M. excoriata, Neohygrophorus verrucosporus nom. prov. Pluteus atromarginatus, Russula albanoides nom. prov., R. aurea, R. firmula, and R. livescens were also confirmed through DNA sequence alignment of their ITS regions. The Basidiomycetes of Mansehra District were sorted out into four major groups i.e. Homobasidiomycetes, Gasteromycetes, Urediniomycetes and Ustilaginomycetes represented by 29, 12, 40 and 20 taxa, respectively. The species of Homobasidiomycetes were placed in 16 genera viz. Agaricus, Amanita, Boletus, Canthrallus, Coprinus, Ganoderma, Hemipholiota, Hydnum, Hymenopellis, Lactarius, Lepista, Macrolepiota, Neohygrophorus, Pluteus, Russula and Tricholoma. The taxa Vbelonging to Gasteromycetes were placed in 9 genera viz. Astraeus, Bovista, Calvatia, Crucibulum, Cyathus, Geastrum, Lycoperdon, Phallus and Pisolithus. The identified species of Urediniomycetes were sorted out into 11 genera viz. Aecidium, Cerotelium, Coliosporium, Phakopsora, Phragmedium, Puccinia, Ravenelia, Tranzschelia, Uredopeltis, Uredo and Uromyces. Whereas all the identified Ustilaginomycetes were placed in 5 genera viz. Bauhinus, Graphiola, Sporisorium, Urocystis and Ustilago. The research endeavor has contributed eight new taxa to science, 24 taxa as new record for Pakistan, 20 taxa as new record for Khyber Pakhtunkhwa Province and 20 taxa as new reports from District Mansehra. Among the taxa new to science are Amanita ohgiensis nom. prov., Hymenopellis luteus nom. prov, Neohygrophorus verrucosporus nom.prov. and Russula albanoides nom. prov. (Homobasidiomycetes), Lycoperdon alpinum nom. prov. (Gasteromycetes), Puccinia brassicae nom. prov. and P. inconspicua nom. prov. (Urediniomycetes) and Sporisorium pakistanense Denchev, T. Denchev & Fiaz (Ustilaginomycetes). The 24 taxa recorded for the first time from Pakistan include Amanita oblongospora, A. hemibapha subsp. hemibapha, Lactarius pterosporus, Macrolepiota dolichaula, M. excoriata, Pluteus atromarginatus, Russula firmula, R. ilicis, R. livescens, R. rubescens and R. silvicola (Homobasidiomycetes), Calvatia lilacina, Crucibulum parvulum, Phallus hadriani (Gasteromycetes), Puccinia dolosa var. circumdata, Uromyces ferulae, Aecidium saussureae-affinis, A. quintum (Urediniomycetes), Bauhinus tenuisporus, Sporisorium linderii, S. dinteri, S. lingii, Urocystis oryzopsidis and Ustilago calamagrostidis (Ustilaginomycetes). The telial stages of two Uredinales viz. Cerotelium fici and Phakopsora ziziphi-vulgaris have also been added to the Rust Fungi of Pakistan. The taxa reported for the first time from Khyber VIPakhtunkhwa Province are Amanita pakistanica, Boletus barrowsii, Hemipholiota populnea, Russula sardonia, Tricholoma atrosquamosum var. squarrulosum (Homobasidiomycetes), Lycoperdon excipuliforme, Cyathus stercoreus (Gasteromycetes), Coliosporium lycopi, Phakopsora ziziphi-vulgaris, Phragmedium rubi-idaei, Ph. mysorense, Puccinia cynodontis, P. echinopis, P. tricholepidis, Uromyces clignyi, U. lespedezae- procumbentis, U. rumicis (Urediniomycetes), Sporisorium moniliferum, S. schweinfurthianum and Ustilago cynodontis (Ustilaginomycetes). The newly reported species from Mansehra District include Agaricus augustus, Ganoderma lucidum (Homobasidiomycetes), Pisolithus tinctorius (Gasteromycetes), Cerotelium fici, Puccinia oahuensis, P. versicolor, Ravenelia taslimii, Tranzschelia discolor, T. pruni-spinosae, Uredopeltis chevaleri, Uromyces decorates (Urediniomycetes), Graphiola phoenisis, Sporisorium andropogonis, S. chrysopogonis, S. cruentum, S. relianum, S. sorghi, S. tenue, Ustilago trichophora and U. Tritici (Ustilaginomycetes). The remaining 29 taxa that have already been reported from District Mansehra were redescribed to upgrade their existing descriptions and also to represent the spectrum and species diversity of Basidiomycetes of District Mansehra. Furthermore 21 host plants have been recorded for different Uredinales of Pakistan, while 10 plant species are recorded as new hosts for Smut fungi in Pakistan. This serious attempt to explore the floristically rich area of District Mansehra for species diversity of Basidiomycetes has not only upgraded the existing information/literature regarding the Basidiomycetes of Pakistan but has also established a standard bench mark for future research endeavors.