A DissertationUnderstanding the livelihoods related impacts of soil and water conservation and decision behaviours of smallholder farmers would be a significant step toward improving environmental conditions, while ensuring sustainable and increased agricultural production. Hence, the objectives of this study include: analysis of households‟ food insecurity and vulnerability to food insecurity and its influencing factors; assessment of factors affecting choice decision of soil and water conservation structure, and evaluation of impact of soil and water conservation adoption on food insecurity and related vulnerability outcomes of farming households. A multi-stage stratified sampling procedure was used to identify a sample of 408 sample households (200 adopters and 208 non- adopters) and also 790 plot-level observations from three districts in eastern Ethiopia. The study used both primary and secondary data. To address the research objectives, the study used descriptive statistics and various econometric models. The logit model results show that food insecurity of farm households was significantly influenced by age of household head, family size in adult equivalent, use of irrigation, adoption of soil and water conservation, and coping strategies. The Three-step Feasible Generalized Least Squares estimation results indicate that age of household head and family size were found to have a negative and significant influence on expected food consumption expenditure. Furthermore, using improved seed, total cultivated land, using soil and water conservation, received credit were significant predictors with positive influence on expected food consumption expenditure. Based on the intensity of their vulnerability, households were grouped as chronic food insecure (24.27 %), transient food insecure (11.77 %), highly vulnerable-food secure (18.38 %), and low vulnerable-food secure (45.59 %). Moreover, the study indicated that 54.01 % of households are vulnerable to food insecurity, which is by higher than the current incidence of food insecurity (36.02 %). The multivariate probit estimation results indicated that out of hypothesized explanatory variables education level, family size income, contact with development agent and erosion problem, livestock ownership, age and sex of household head, number of plots, off-farm activity and received credit were significant factors for farm-level adoption of stone bund, soil bund and bench terracing conservation technologies. Endogenous switching regressions and propensity score matching result indicated that, adoption of soil and water conservation not only positively impacts the per capita food consumption expenditure and net crop value, but also significantly reduced the probability of farmers being food insecure, vulnerability to food insecurity, as well as being transient and chronically food insecure.