A field experiment was conducted on vertisol at Ambo University College (Ethiopia) during 2003/2004 and 2004/2005 cropping seasons to investigate the response of tomato cultivars varying in growth habit to rates of Nitrogen (N) and Phosphorus (P) fertilizers and plant spacing. The treatment consisted of factorial combination of two cultivars (Margelobe and Melka shola), three NP fertilizers rates (50 kg N + 60 kg P2O5/ha, 80 kg N + 90 kg P2O5/ha and 110 kg N + 120 kg P2O5/ha) and three spacing (100 cm x 30 cm, 80 cm x 30 cm and 60 cm x 45 cm) arranged in a Randomized Complete Block Design. Results revealed that fertilizer rates and spacing significantly affected the total and marketable fruit yields as well as % marketable fruit yield. Similarly, plant vigor (plant height), number of fruits per cluster and 10 fruit weight were significantly influenced by all of the main factors. Besides the main factors effect, fertilizer rate*spacing and cultivar*spacing interaction effects were also observed on % marketable fruit yield and 10 fruit weight, respectively. The results of 2003/2004 cropping season showed that the application of 110 kg N + 120 kg P2O5/ha or 80 kg N + 90 kg P2O5/ha resulted in significantly higher total as well as marketable fruit yield of the tomato cultivars. Result of 2004/2005 cropping season, however, demonstrated that only the application the highest fertilizer rate (110 kg N + 120 kg P2O5/ha) resulted in superior fruit yields whilst the other two rates did not significantly differ from each other in affecting fruit yields. Results of both cropping seasons confirmed significantly higher % marketable fruit yield due to the application of either 110 kg N + 120 kg P2O5/ha or 80 kg N + 90 kg P2O5/ha. Closer spacing of 80 cm x 30 cm and 60 cm x 45 cm gave higher total as well as marketable fruit yield than the wider spacing of 100 cm x 30 cm. Na Ambo University College v Etiopiji je bil v letih 2003/2004 in 2004/2005 izveden poljski poskus z dvema kultivarjema paradižnika (determinantnim in nedeterminantnim) da bi raziskali vpliv gnojenja z dušikom (N) in fosforjem (P) ter razdalje med rastlinami na paradižnik. Izveden je bil faktorski poskus z dvema kultivarjema (Margelobe in Melka shola), tremi odmerki gnojil NP (50 kg N + 60 kg P2O5/ha, 80 kg N + 90 kg P2O5/ha in 110 kg N + 120 kg P2O5/ha) in tremi razdaljami med rastlinami (100 cm x 30 cm, 80 cm x 30 cm in 60 cm x 45 cm) v naključnem bloku. Rezultati so pokazali, da so stopnje gnojenja in gostota rastlin značilno vplivali na celoten in tržen pridelek raslin, kot tudi na odstotek uporabnega pridelka. Podobno so bile višine rastlin, teža in število plodov v značilni povezavi z vsemi glavnimi faktorji. Poleg glavnih vplivom so vplivale tudi interakcije gnojenje*gostota in kultivar*razdalje tako na % tržnega pridelka plodov kot na težo 10 plodov. Rezultati v sezoni 2003/2004 so pokazali da je uporaba 110 kg N + 120 kg P2O5/ha ali 80 kg N + 90 kg P2O5/ha omogočila značilno višje celokupne in tržne pridelke paradižnikov pri obeh kultivarjih. Toda v sezoni 2004/2005 je samo najvišji odmerek gnojil (110 kg N + 120 kg P2O5/ha) dal višje pridelke. Rezultati obeh sezon skupaj so potrdili višji % tržnega pridelka pri uporabi 110 kg N + 120 kg P2O5/ha ali 80 kg N + 90 kg P2O5/ha. Gostejša saditev (80 cm x 30 cm oziroma 60 cm x 45 cm) je dala višje pridelke kot redkejša saditev (100 cm x 30 cm).