This paper presents results on the field performance degradation of mono-crystalline silicon PV modules from 11 PV module manufacturers under identical field conditions. The modules were installed in both fixed tilt and manual tracking modes. The data were monitored using a CR23X Data logger and I-V curves were taken using SPI 240A Sun simulator. The performance parameters analyzed are V(oc), I(sc), P(max), I(mp), V(mp) and the fill factor, as a function of time of field exposure. Qualitative studies are made on physically visible defects such as EVA coloration, cell de-laminations, corrosion of solar cell grid, corrosion of end strip connected in the terminal box, failure of by-pass diode, detachment of the terminal box, tearing of tedlar sheet, etc. The effect of field exposure on the performance parameters indicates that the qualification standard (s) needs to be reviewed and revised if the modules are to perform for similar to 20 years under actual field conditions in India. (C) 2010 Elsevier B.V. All rights reserved.