Abstract: An experiment was conducted under greenhouse condition to study the morphological, physiological and biochemical changes in tea plants due to Phomopsis infection. Physiological responses of tea plants to infection in term of photosynthetic rate, transpiration rate, stomatal conductance, water use efficiency and total chlorophyll content were studied in susceptible TRI-2024 and tolerant TRI-2025 cultivars. In addition, growth characteristics such as height, dry weight and plant strength and biochemical parameters such as total sugar, nitrogen, amino acids, protein, polyphenols and catechins of infected and healthy plants were also studied. The results revealed that all the growth characteristics, physiological and biochemical parameters were reduced significantly in infected plants rather than healthy plants. However, the reduction was more prominent in susceptible cultivar than in tolerant ones. Clonal susceptibility of a few tea cultivars was tested by inoculating the pathogen onto susceptible and tolerant clones. A clear variation in the size of the canker was noticed in the susceptible TRI-2024 and tolerant TRI-2025 cultivars.