•Simultaneous integrated boost seems effective and safe when given hypofractionated whole-breast irradiation.•The prescribed dose to the whole breast varied from 40 to 46.8 Gy. The number of fractions varies from 15 to 20 fractions.•The prescribed dose per fraction to the boost varied from 2.4 Gy per fraction to 3.4 Gy per fraction for a total boost dose from 48 to 52.8 Gy.•Regarding local control, no study reported local recurrence in patients treated with simultaneous integrated boost. Several studies have shown that simultaneous integrated boost provides better dose homogeneity, improves the biologically effective dose-volume histogram and reduces treatment time compared to sequential boost in breast cancer. We conducted a systematic review of published trials evaluating simultaneous integrated boost in hypofractionated radiotherapy to analyze the results in terms of overall survival, local control, early and late side effects, and radiotherapy techniques used. Upon 9 articles, the prescribed dose to the whole breast varied from 40 to 46.8 Gy. The number of fractions varies from 15 to 20 fractions. The prescribed dose per fraction to the boost varied from 2.4 Gy per fraction to 3.4 Gy per fraction for a total boost dose from 48 to 52.8 Gy. Simultaneous integrated boost seems effective and safe when given hypofractionated whole-breast irradiation but needs to be validated in prospective trials. Display omitted