Blackberry mutants were induced by the irradiation of blackberry shoots with 5 kilo radians of cobalt ($^{60}Co$) gamma irradiation. Seven mutant plants demonstrating improved plant growth properties were selected for evaluation of the fruit quality characteristics, such as size, shape, color, firmness, soluble solids content, juice acidity, nutritive value (e.g. ascorbic acid) and overall fruit flavor. The organoleptic properties, including texture, firmness, flavor, sweetness, acidity, color, and overall fruit flavor, were evaluated by a consumer panel. The results indicated that irradiation induced changes in some of the quality parameters of blackberry fruits, as well as increased the fruit shelf-life.