Heat waves fall under the category of weather-climatic risks that increasingly affect socio-economic activity, often having serious consequences on agriculture and the state of the environment. In the climate observations of the Republic of Moldova, heat waves are highlighted by tropical days (maximum daily temperature ≥30°C), hot days (maximum daily temperature ≥33°C), respectively tropical nights (minimum daily temperature ≥20°C). The study carried out consisted in establishing the impact of the heat waves of the last two decades on the size and quality of the sunflower yield in the Republic of Moldova. Instrumental measurement data, collected from the archives of state institutions in the respective field, were used as primary materials for the study. The mentioned data were systematized, processed, interpreted graphically and cartographically, with the use of statistical programs - Statgraphics, Instat Plus and QGis, in accordance with the proposed objectives. In the Republic of Moldova, during the last 23 years, absolute maximum temperatures have recorded high values and increased frequency: between 30.0 and 32.9°C – 684 cases; between 33°C and 34.9°C - 270 cases; between 35°C and 39.9°C – 185 cases; temperatures ≥ 40.0°C – 8 cases. In all these years, temperatures ≥ 33.0°C were recorded. But these warm-ups can have a different effect. In the last two decades, an expansion of temperatures ≥ 30°C and ≥ 35°C is increasingly observed, being a possible consequence of global warming. The most intensive and prolonged heat waves during the study period were recorded in the warm season of 2007, 2012, 2015, 2020 and 2022, when the sunflower yield was significantly reduced. For example, performing a comparative analysis of the average yield per 1 ha of sunflowers in 2020 with the corresponding yield in 2019 and with that of the previous 10 years (2010-2019), allowed establishing the impact of the intensive and long heat waves in 2020 on the average sunflower crop in administrative-territorial profile, being compromised by about 50% of its size compared to that of 2019.