The objective of this work was to study process for Greek-style yogurt (GSY) , Using probiotic bacteria strain Lactobacillus plantarum ACA-DC 146 and L. paracasei subsp. tolerans ACA-DC 4037.Both strains displayed acidification activity,Firmness and Viscosity. Yoghurt produced with L. paracasei subsp. tolerans ACA-DC 4037 exhibited the best sensory properties, with a rich traditional smooth taste. Yoghurt produced with this strain as an adjunct had good physicochemical properties. After 2 weeks of refrigerated storage, gave yoghurt with long fermentation times and poor organoleptic properties. Next using micellar casein concentrate (MCC) obtained from milk by microfiltration. Two MCC preparations with 58 and 88% total protein (MCC-58 and MCC-88).Strained GSY of similar protein content was used as the control. Yogurt milk bases were inoculated with 0.02% (wt/wt) or 0.04% (wt/wt) direct vat set starter culture and fermented until pH 4.5. the rheological analysis at 37°C and 42°C showed the flow rate,viscosity and Consistency for all GSY samples. Differences in the magnitude of viscoelastic parameters between the 2 types of GSY were found, with elastic modulus of MCC-fortified GSY < elastic modulus of control, indicating a different extent of protein interactions in the 2 types of yogurt.