In this study, an original and green procedure of processing waste of the citrus fruits was developed using the concept of bio-refinery, innovative techniques “ultrasound”and “micro-wave”, and a green sol- vent “limonene”to recover carotenoids. Essential oil extraction was performed by Solvent Free Microwave Extraction (SFME) and compared to steam distillation (SD). The essential oil yields were comparable for both processes: 4.02 ±0.23% for SFME and 4.16 ±0.05% for SD. After that, carotenoid extraction from cit- rus peels was performed by ultrasound-assisted extraction (UAE) and conventional extraction (CE) using d -limonene obtained starting from essential oil, as a solvent, and then compared to n-hexane extract. Response surface methodology (RSM) using central composite designs (CCD) approach was launched to investigate the influence of process variables on the ultrasound-assisted extraction (UAE). The statisti- cal analysis revealed that the optimized conditions of ultrasound power, temperature and time were 208 W cm −2 , 20 °C and 5 min giving carotenoid content of 11.25 mg L −1 . Compared to the conventional ex- traction, (UAE) gave an increase of 40% in carotenoid content. The comparison to n-hexane extract gave no significant changes in carotenoid content. Combination of microwave, ultrasound and d -limonene ob- tained from a bio-refinery of a by-product of citrus fruits industry allow us to develop a very good envi- ronmental green approach giving high added values compounds, with a saving of time, and a complete valorisation of waste.