The aim of this study was to produce a probiotic yoghurt (from cow's milk) effective against obesity, in which 2%, 3% and 4% green tea (Camellia sinensis) was added and Streptococcus thermophilus and Lactobacillus gasseri cultures were used in a 1/1 ratio. On all storage days (1, 7, 14, 21), yoghurt samples showed statistically significant differences in terms of pH (4.34-4.76), titratable acidity (1%-1.24%), dry matter (17.84%-20.70%), serum separation (20.80%-28%) and water holding capacity (49.8%-56.9%). The difference between storage days is also significant. Phenolic substance content increased as the amount of green tea increased. During storage, phenolic content varied between 33.18-45.29 gallic acid (GLA) mg/kg in control yogurt, and 203.14-565.43 GLA mg/kg in green tea-containing yogurts. The decrease in the L* value and the increase in the a* and b* values were caused by the addition of green tea and the increase in the amount of green tea added. Increasing the amount of added green tea resulted in an increase in the flow behavior index. The sample containing 2% green tea was the most liked among the green tea samples. In that sample, Lb. gasseri number was above the lower limit (1.53×106 - 9.47×106 cfu/g) for a food to be considered probiotic during storage. It was concluded that in order for a product to maintain its probiotic properties during storage, the rate of inoculated starter culture should be high. The amount of Lb. gasseri added to the milk from which yoghurt will be made should be increased.