Critiques of the new technology in agriculture have expressed its class, technological, regional and crop bias. They call for expanded research to cover more crops suited to ecologically marginal areas, agrarian reform to distribute its benefits and the generation of mechanical technology and institutions amenable to the poor. Ethiopia experienced both the dissemination of the new technology (first in 1967 in the Arsi Region and as of 1970 in limited parts of the country as a whole) and a radical redistributive agrarian reform (since 1975) aiming at a socialist transition in agriculture. A micro level analysis of output and input in 30 farms disaggregated into the pre and post technology period on the one hand and poor/lower middle and rich peasants on the other is built upon to assess the effect of the new technology on production, factor productivity, the social differentiation of the peasantry, changes in the form and extent of the marketed surplus and prices in 1966-1975 (post technology, pre-agrarian reform) and 1975-1980 (post new technology and post agrarian reform) in the Arsi Region. This is further extended to Ethiopian agriculture as a whole including the countrywide redistributive impact of the reform, government intervention in marketing and the terms of trade. The study argues that given the non-feudal, non-capitalist agrarian class formation in rainfed single cropping 'land surplus' agrarian economy, redistributive agrarian reform, state intervention with high marketing cost and the accumulation of merchant capital not reinvested into agriculture meet neither the redistributive nor the accumulation objectives of development.