In this work the effect of prevailing electrical and thermal conditions on the luminous of efficacy of radiation and wall-plug efficiency of phosphor-converted white LEDs is discussed. For this study, LED manufactured by a reputed lighting company is used. Previous studies have modeled the spectral power distribution of white-pc LEDs as a function of the temperature and electrical characteristics. Results from the study confirm that the nature of spectral power distribution does not change with electrical or thermal conditions thereby giving constant luminous efficacy of radiation. However, it is found from the study that there is significant effect of electro-thermal conditions on the luminous efficacy of the system, with wall-plug efficiency decreasing drastically with increased forward current. However, it must be noted that effect of thermal conditions is comparatively less on the working of white-pc LED compared to the effect of electrical conditions. Spectral power distributions are obtained for different electro-thermal combinations, and they indicate that nature of the spectral power distribution remains same irrespective of the prevailing electro-thermal conditions.