The combining ability for grain yield of nine early maize lines was evaluated by means of Savchenko’s method. The trials were curried out in the fields of the Maize Research Institute in Knezha during the 2012–2014 period. The experimental hybrids were tested under conditions of no watering and plant density of 5,800 plants/da. Lines КА 0 302, КА 79 312 and КА 97 304 showed the highest General Combining Ability. These lines will be included as components of high-yielding middle early synthetics or as testers in analyzing crosses to determine the General Combining Ability in the early stages of the selection process. Lines КА 92 306, КА 0 303 and КА 89 304 were of high Specific Combining Ability. They could be used in the heterosis breeding for developing of high productive maize hybrids.