The objective of this research was to study the effects of mixed viral infection and growth stage on chilli (Capsicum annuum L.) production. This study was carried out in a split plot design with plant stage as the main plot and viral infection as the sub-plot. Plant stage as the main plot consisted of four levels, i.e 15 days, after transplanting (DAT), 40 DAT, 65 DAT, and 90 DAT, whereas viral infection as sub-plot consisted of 5 innoculation of viruses, i.e., no viral infection (control), cucumber mosaic virus (CMV) + tobacco mosaic virus (TMV), cucumber mosaic virus (CMV) + potato virus Y (PYV), CMV+PYV and CMV+PYV+TMV. Each treatment was replicated five times. The inoculations were conducted mechanically by rubbing single young leaves which had been dusted with carborandum 400 mesh, with inoculum of respective viruses. Parameters observed in this research were plant height, biomass, and chillies production (number of fruits and the weight of total fruits yield) for each plant. Results of the study showed that that growth stage and viruses significantly affect the plant height and yield components of chilli. Mixed viral infection among CMV, PYV and TMV caused a significant reduction in the chilli biomass and production. Although viral infection increased the plant height, the infected chilli seemed unhealthy. There existed interaction effects of mixed viral infection and growth stages on the chilli biomass. All viral infection and growth stages reduced significantly the biomass of the chilli, with the lowest found at the mixed viral infection of TMV+PYV (18.5%) and the highest was at CMV+TMV (44%). Double mixed infection of CMV+TMV and CMV+PYV caused 52 and 49% reduction of both the total number of fruits and total weight of fruits/plant respectively being the highest reduction compared to other treatments.