In this study, CdSe nanocrystals (NCs) were synthesized by inexpensive, non-toxic, and eco-friendly method, and the effect of growth temperature on the formation of CdSe NCs was investigated. The NCs were formed using oleic acid, and paraffin liquid instead of environmentally harmful materials typically involved in the NC synthesis. As the growth temperature increased from 140 degrees C to 220 degrees C, the diameter of CdSe NCs was changed from 3nm to 4.5nm, and the activation energy for the growth of CdSe NCs was 8.1 J/mol. As-synthesized CdSe NCs had a hexagonal crystal structure with wurtzite phase, and the growth of (101) plane was preferred with increasing growth temperature. The energy band-gap of the NCs was shifted from 2.29eV to 2.18eV, and the band-gap shift had a linear relationship with the size increase of the NCs. The growth temperature for the formation of CdSe NCs was an important factor to control the properties of the NCs. The developed method is considered to be an efficient CdSe synthesis method using eco-friendly colloidal route.