Aroma is one of the essential factors for evaluating fruit quality, and the volatile constituents in mini-watermelon fruits were here determined by a headspace-solid-phase micro-extraction and gas chromatography-mass spectrometry method (HS-SPME-GC-MS). The plants, Citrullus lanatus [Thumb.] Matsum. and Nakai cv. Minirossa (Cucurbitaceae), were cultivated in Pachino, Sicily (Italy) under greenhouse conditions. The fruits were collected in two different production years. Sixty-eight volatile compounds have been identified and quantified; among these, the impact aroma compounds are also included. The volatile compounds have been identified by linear retention index, mass spectra, standard injection and reference data; the quantification has been carried out by the standard addition technique. The main compounds were (Z)-3-nonen-1-ol, (E)-2-nonenal and (Z, Z)-3,6-nonadien-1-ol, which are characteristic volatiles in the Cucurbitaceae family.