Brazil is the largest producer of sugar and one of the biggest consumers of the world, exemplified by the consumption of 8.04 kg for crystal sugar per capita/year and 3.16 per capita/year kg for refined sugar (types more consumed). High levels of impurities compromise the quality of the sugar, because these are correlated with the formation of alcoholic flakes, increase of the viscosity and affect the sweetness. This paper aims to quantify the vegetable impurities in sugar, as starch. Twelve samples of sugar from Piracicaba’s market were analyzed, with 3 samples of each type of sugar (raw, refined, crystal and brown). It was also studied important standards (polarization, humidity and insoluble residues) to feature the samples. The analysis occurred in a laboratory suitable for sugar analysis and it was applied Copersucar Official Methods. The amount of insoluble residue were about 35 times higher than the maximum limit (60 mg kg-1) and 50% of the samples had less than 99% index polarization (it was unconsidered brown sugar in this measure). The humidity analyses in all samples are in accordance with the standards (exceptions were 1 sample of brown and 1 of crystal sugar). Starch patterns were over the maximum established to all samples (180 mg kg-1), what can be explained by the variety of sugar cane used and by the shift of the type of harvesting (mechanized). This brought more starch and polysaccharides to the mills and the products. Samples with higher content of starch (over 250 mg kg-1) showed levels 4 and 5 of alcoholic flakes content. The analyses showed that vegetable impurities in sugar are higher than the standards what depreciate sugar quality (sweetness and purity, mainly) and affect culinary appliance (turbidity and precipitation of starch). Therefore, is important improve process of producing and industrial quality control of sugar.