The sensitivity of Amaranthus hybridus physiological parameters to Telfairia mosaic virus infection was investigated. To achieve this, seeds of A. hybridus were obtained from plants monitored on the field for virus symptoms expression. The seeds were broadcasted on nursery beds, on germination seedlings were transplanted and inoculated with Telfairia mosaic virus. Sensitivity of physiological parameters was assessed by measuring effect of the virus on growth, yield, leaf nitrogen, relative water content and photosynthetic pigments at different stages of growth for 12 weeks after inoculation (WAI). Results revealed high sensitivity of growth and yield parameters of A. hybridus to TeMV infection with significant (P=0.05) reductions. Severe leaf size reduction of (58.8%), stem height (53.7%), number of primary shoot (50.8%) and number of leaves produced (69.9%), leaf fresh weight (56.9%), leaf dry weight (58.0%) at 12 WAI. Shoot fresh weight and root dry weight had reductions of 20.3% and 20.1% at 13 WAI. Shoot DW and root FW revealed less sensitivity to TeMV infection. The virus caused reduction in relative growth rate of (42.0%), net assimilation rate (45.5%) at 4 WAI and leaf area ratio (33.1%) at 12 WAI. Leaf nitrogen content decreased with plant age in both healthy and infected plants with highest decrease of 56.1% at 2 WAI and lowest decrease of 37.1% at 12 WAI. The virus caused reduction in relative water content of 40.0% at 12 WAI. Photosynthetic pigments of A. hybridus were highly sensitive to TeMV infection with reduction in chlorophyll a of (50.8%), chlorophyll b (22.3%), chlorophyll a + b (40.6%) ratio of chlorophyll a/b (36.5%) at 12 WAI and carotenoids (55.1%) at 12 WAI. Chlorophyll a was more sensitive to TeMV than chlorophyll b. The sensitivity of A. hybridus to TeMV disrupted physiological processes which affected growth and yield with resultant effect on low income earnings of growers.