Bitter leaf or Vernonia amygdalina Del. is a functional food plant known for its strong antioxidant activity. It is consumed as vegetable and often used in the treatment and medicine of various diseases. Green grass jelly or Cyclea barbata Miers is known as cincau hijau and has been commonly consumed in Indonesia. It is considered to have high antioxidant activity and thus a potential source of antioxidant. Meanwhile, non-dairy yoghurt such as cowpea yoghurt is a vegetable milk derived functional food by which the cowpea (Vigna unguiculata) itself provides the benefit of having high protein content but low fat content. The objective of this research was to study the antioxidant characteristics of cowpea yoghurt added with African bitter or green grass jelly leaf crude extract. The crude extract of African bitter leaf has the antioxidant activity of 76.765±2.261 ppm, total phenolic content of 61.787±0.518 mg GAE/g and total flavonoid content of 56.063±4.688 mg QE/g. The crude extract of Green grass jelly leaf crude extract has the antioxidant activity of 140.079±2.532 ppm, total phenolic content of 30.252±0.941 mg GAE/g and total flavonoid content of 10.786±0.017 mg GAE/g. Different concentrations of African bitter leaf and green grass jelly leaf crude extract (0, 1, 2, 3%) were added to the cowpea yoghurt incubated for different period of time (14, 18, and 22 h) to observe their antioxidant characteristics. Three best cowpea yoghurts were selected based on antioxidant characteristics and subjected to sensory evaluation by 70 panelists to see their acceptance towards the sample. The results showed that cowpea yoghurt with 2% African bitter leaf crude extract with fermentation time of 14 h and cowpea yoghurt with 2% Green grass jelly leaf crude extract with fermentation time of 18 h were selected by the panelists with the antioxidant activity of 3,661±62.579 & 8,871±245.888 ppm, total phenolic content of 413.117±6.800 & 369.772±1.162 mg GAE/L and total flavonoid content of 40.439±2.535 & 37.078±3.102 mg QE/L, respectively.