Mango (Mangifera indica) is one of the popular fruits in Ethiopia and many other tropical countries. Mango seed weight is 30 − 45% of total fruit weight which completely goes off as waste. In this study, Mango seed kernel (MSK) was selected as a feed for production of MSK starch based textile sizing agent. Effect of extraction conditions on starch yield has also been investigated the Starch yield was increased from 29.82% to 44.24% with increasing the % of SO2 concentration and steeping time. Starch separated from kernel was investigated for physicochemical and thermal properties. MSK starch had pH of 3.9, Ash content was found to be 0.26% while moisture content was 13.8%. Amylose content observed for MSK starch was found to be 14.08%, Swelling Power values were significantly higher than 17.26 to 18.00g/g obtained from Horse gram starch but lower than those reported for rice starch. Thermal characteristics of MSK starch was analyzed by means of differential scanning calorimetry (DSC). PHI, a measure of uniformity in gelatinization, was found to be higher in isolated mango starch (8.88). The value of Rg (gelatinization range) was 120.34, which is high. MSK starch modified by oxidation and acid-hydrolysis was characterized by FTIR and apparent viscosity of its slurry was also measured by VISCO Star plus H viscometer. From the result both modified MSK starch and native MSK was shown almost the same FTIR spectra and also higher reduction in viscosity of both modified MSK starch was observed. The Effect of MSK, OMSK, HMSK, PVA and combination of PVA with modified MSK starch size material type slurry as a warp sizing agent on the physico-mechanical properties of fine cotton yarns was also investigated. It reviles that fine cotton yarns sized with OMSK and HMSK had increased tensile strength by nearly 18% and decreased elongation at break than the unsized ones by nearly 24%. Besides, fine cotton yarn treated with the OMSK and HMSK slurry had obviously decreased hairiness index and slightly increased abrasion resistance, and OMSK and HMSK slurry had good adhesion. Overall, weaveability of modified MSK starch sized yarns is better than natural MSK starch but slightly lower than PVA and mixture of PVA and modified MSK. Percent of size removal at different water rinsing ratio for all size recipes was also determined. From the results, sufficient size removal was observed at 1:20 water rinsing ratio for all size types. Acid modified MSK and oxidized MSK shows promising result of desizability than the other size types. In general, synthesized OMSK and HMSK slurry may find promising application as a novel highperformance warp sizing agent for fine cotton yarns.