Baby corn is a premature ear of maize that is harvested as dehusked vegetable corn at 2-3 days after silking before fertilization. No enough attention has been paid to this kind of maize in the literature. In order to investigate the effect of planting density and pattern on yield and some qualitative and morphological traits in baby corn hybrid KSC403su a field experiment was conducted at College of Agriculture, Shiraz University, Shiraz, Iran in 2014. The treatments were plant density at four levels: 100, 125, 150 and 175 thousands plant ha-1 and three planting patterns: one, two and three rows which arranged in factorial based on a randomized complete block design (RCBD) with three replications. The results showed that yield, solar radiation, total soluble solid (TTS) and a majority of morphological traits of baby corn were significantly affected by the treatments and their interactions. With increasing of the number of rows and plant density, leaf area and  plant height were increased, while the number of tillers per plant, number of ears per plant, husked and dehusked ear yield, husked and dehusked ear weight and ear diameter were decreased. The highest husked and dehusked ear yield were obtained in 150 thousands plant ha-1 and single row planting pattern with average of 1834 and 9128 Kg ha-1, respectively. In general, one row planting pattern at 150 thousands plant ha-1 were considered as the most suitable treatments and could be suggested for achieving acceptable yield and appropriate quality.