This study was carried out in the Teaching and Research Farm of Delta State University, Asaba Campus (Nigeria) from March to December in 2008 and replicated between March and December, 2009, to evaluate the effects of variety and spacing on yield indices of Open-pollinated maize. It was a factorial experiment carried out in a Randomized Complete Block Design (RCBD) with four replicates. Four open-pollinated varieties (Suwan -1- SR, ACR97, BR9922-DMRSF2 and AMATZBRC2WB) were evaluated under three different plant spacing for such yield indices as number of cobs/plant, cob length, grain weight and number of grains/cob of maize. The results obtained indicated that variety BR9922-DMRSF2 was outstanding with number of cobs/plant of 1.7 in both 2008 and 2009, cob length of 27.7 cm and 26.7 cm in 2008 and 2009, respectively. Its grain weight was 4.7 t/ha in 2008 and 4.9 t/ha in 2009, and its number of grain/cob was 467.7 in 2008, and 463.9 in 2009. Plants sown at spacing of 75 cm x 15cm had higher number of cobs/plant of 1.9 in both 2008 and 2009.Their grain weights (t/ha) were 5.0 in 2008 and 5.2 in 2009, their cob lengths were 18.6cm in 2008 and 20.1cm in 2009, while their number of grains/cob were 363.0 in 2008, and 369.0 in 2009. The results of interaction showed that except variety x space, the parameters investigated were all significantly (P < 0.05) different and affected yield indices of open-pollinated maize. Based on the findings of the study, it was recommended that (i) open-pollinated variety BR9922-DMRF2 be grown in the study area for increased grain yield indices of maize. (ii) Plant spacing of 75 cm x 15 cm which resulted in higher number of cobs/plant and higher grain weight be adopted in maize production.