The objective of this paper is twofold. First, using a three rounds panel data of 7110 households, we investigate the adoption decisions and the complementarities among the four labor-intensive technologies (agricultural extension service, irrigation, soil conservation and planting seeds in a row) and a comprehensive use of four modern inputs (improved seed variates, inorganic fertilizer, pesticides, organic fertilizer) which have been frequently adopted by smallholder farmers. Second, controlling for the dynamic effects of wealth, previous technology ad options and other cofounders, we estimate the impact of agricultural extension services and other multiple technology adoptions on food and nutrition security of the smallholder farmers in Ethiopia. The estimation results indicate that a significant complementarity between modern inputs and labor-intensive technologies. This suggests that the adoption of modern inputs induces farmers to adopt labor-intensive technologies and vice versa. In addition, our finding suggests that farmers who adopt technologies once are more likely to adopt the technologies again, reflecting the profitability of agricultural technology adoption. Our finding also indicates that agricultural extension services and technology adoption have a statistically significant and positive impact on nutrition and food security.