Wheat (Triticum aestivum L.) endosperm texture in is an important criterion that affects milling and end-product quality. Grain hardness is controlled by the Ha locus located on chromosome 5DS. The Ha locus contains the puroindoline a (Pina) and puroindoline b (Pinb) genes. To date, all hard wheats surveyed possess mutations in Pina or Pinb while soft wheat possesses both wild type Pina and Pinb. Our objective was to determine the role of Pina and Pinb individually and in combination upon grain hardness and starch binding. Transgenic Pina or Pinb lines were crossed to hard wheats that were either Pina or Pinb null. The segregating population randomly varied for the transgene and the Ha locus.  Addition of Pina to Pinb null and Pinb to Pina null resulted in intermediate textured grain. Soft endosperm texture was obtained only when both Pina and Pinb were present with the softest grain observed with addition of Pinb to Pinb null. In addition, association of puroindoline to starch required both PINA and PINB, however high levels of either PINA or PINB gave weak binding and intermediate textured grain. The results indicate that either PINA or PINB can act in the absence of the other leading to intermediate textured grain but soft grain texture occurs only when both are present.