Upland rice is a major cereal crop in Libokemkem district. However, yield of the crop is low due to lack of site specific seeding rate and inter-row spacing recommendation. Hence, a field experiment was conducted in Libokemkem district at bura kebele during the main rainy season of 2018 to assess the effect of seeding rate and inter-row spacing on grain yield and yield component on upland rice under rain-fed conditions. Two factorial combinations of seven seeding rates (40, 60, 80,100,120,140 and 160 kg ha-1) and four inter-row spacing (15, 20, 25 and 30 cm) were used. The treatments were arranged in Randomized Complete Block Design with three replications. Data of phenological, vegetative growth and yield and yield related parameters were collected timely following their standard methods and procedures. All data were analyzed by using SAS 9.0 version and mean separation for significant treatments were done by least significance difference. The result of the present research showed that except for thousand seed weight all parameters highly significantly affected by main effects of seeding rate. In addition, plant height, panicle length and grain yield were highly significantly affected by main effects of inter row-spacing. Grain yield and harvest index were also significantly affected by the interaction effect. The highest grain yield was obtained (5.20 t ha-1) at interaction effects of seeding rate and inter-row spacing at 100 kg ha-1combined with 15cm, respectively. The treatment combination 100 kg ha-1with 25 cm inter row spacing had given the highest net benefit with acceptable range of marginal rate of return. Therefore, application of 100 kg ha-1 seeding rate and 25 cm inter row spacing is economically feasible and can be recommended for the study area. Key words: Grain Yield, Inter-Row Spacing, Interaction Effect, Seeding Rate, Upland Rice 1 Chapter 1. INTRODUCTION 1.1. Background