Background: Subsistence farming in West Abaya district is sited in an area prone to drought. Thus, poor food security is a principal concern. But, this has been less documented. Therefore, this study aimed to determine the magnitude of household food insecurity and identify associated factors in West Abaya district, Southern Ethiopia, 2015.Methods: Community-based cross-sectional study was done on 779 households from February to March, 2015. Out of 24 kebeles (lowest administrative units) in the district, 9 kebeles were selected randomly. Then from 9 kebeles, 15 'gots' were selected using probability proportionate to size. Gots are villages in a kebele where a kebele may have up to three of them. Data were collected using pretested structured questionnaire by trained data collectors. The study used a 'Household Food Insecurity Access Scale' to measure access component of household food insecurity. Data were entered in Epi Info version 3.5.4 and exported to SPSS version 20.0 for cleaning and analysis. Binary and multivariable logistic regression was used to identify factors associated with food insecurity in the study area. Results:The overall prevalence of household food insecurity was 38.1% in the study district. Households headed by female were more likely to be food insecure than households headed by males 'AOR = 2.1 (95% CI 1.15, 3.74). ' Households headed by persons aged >65 years were 6.5 times more likely of being food insecure compared to household headed by persons aged 18-44 years, 'AOR = 6.51 (95% CI 3.25, 13). ' The odds of households with larger family size to be food insecure was higher than households with smaller family sizes 'AOR = 2.4 (95% CI 1.7, 3.5). ' Owning smaller farm land increases the risk of being food insecure nearly by 2 times compared to larger land size 'AOR = 1.7 (95% CI 1.12, 2.7). ' Besides, households headed by uncoupled were likely to be food insecure than married 'AOR = 2.6 (95% CI 1.53-4.26). 'Conclusions: This study revealed that household food insecurity was considerable in the study area. Hence, proper attention should be given to increase food production and productivity of the farmers by improving access to farm land, strengthening the efforts of family planning and women empowerment.