Maize (Zea mays L.) is among the most important cereal crops grown and consumed in East Africa. Improved open pollinated maize varieties prevail popular among resource-poor farmers due to their low cost of production. Despite the advantages of OPVs in Uganda current trends show that open pollinated varieties are being continuously replaced by hybrids, and maize production is constrained by foliar diseases and abiotic (drought) factors. Therefore, it has become important to broaden the genetic pool of OPVs by characterising them using agronomic and diseases related traits. In this study, nineteen OPVs and five checks were phenotypically characterised at the National Crop Resources Research Center in α-lattice design. The results showed highly significant (P < 0.001) variations among the local and introduced OPVs in most of agronomic traits, except plant aspect, grey leaf spot and stem borer. An OPV SUWAN showed the highest grain yield (10.22 t ha-1) performance. The least number of days to anthesis, silking and stem lodging was observed on OPV SITUKA MI. Regarding correlation coefficient analysis, the result showed that positive significant (P < 0.001) correlations were observed between days to anthesis and silking (r = 0.99). The highest negative and significant (P < 0.001) correlation was observed between percentage of fuzarium ear rot and number of kennels per row (r = -0.67).