The present invention relates to a system, method and tool for optimizing combination of Light Emitting Diodes (LEDs), and to an optimized combination of LEDs. The system and method provide a plurality of LEDs and corresponding specifications. Then, a color temperature and a color rendering index are selected. Calculations are performed for subgroups of LEDs. At least one optimized combination of LEDs having an optimized corresponding luminous flux is identified according to selected color temperature, color rendering index and LEDs' specifications. In another aspect, the present invention relates to a tool for optimizing white light generated by a combination of LEDs. The tool comprises a repository for storing specifications for the combination of LEDs, a selection module for selecting at least one of the following parameters: a color temperature, a color rendering index and a maximum shift variance from a black body locus, and a processing module for calculating for subgroups of LEDs resulting color temperature, color rendering index, luminous flux, and for identifying an optimized selection of LEDs. The present invention also relates to an optimized combination of LEDs for producing white light with high color rendering index, the combination of LEDs excluding blue LEDs.