In the graduation thesis, we investigated the glucose, fructose and trehalose concentrations in the hemolymph of honeybees from the winter cluster. Hemolymph was sampled from the bees of two different hives from 30.12.2013 to 19.2.2014. During the experiment we have noticed that one of the the two colonies was infected with the microsporidia Nosema spp., which was the main cause for the subsequent death off of the whole colony. Additionally, we performed an experiment where the bees from both hives were exposed to the ideal conditions in the incubator. For the evaluation of the concentrations of sugars in hemolymph samples, the high-performance anion-exchange chromatography with pulsed amperometric detection (HPAEC-PAD) was used. We found that prior the sampling the bees should be narcotized using the ice bath rather than carbon dioxide. Our results were compared with the investigations of the sugar levels on the mature autumn and spring bees and we found out that bees from winter cluster have lower trehalose levels. We also confirmed that trehaloze is an important energy source during flight activity. Low concentrations of the sugar titers in the hemolymph of healthy bees are the consequence of staying in the hive at low outside temperatures. In the bees infected with Nosema spp., this is however the effect of reduced absorption of the sugar from the intestine into the hemolymph. Using the corelation analysis, we established the corelation between sugar titers, especially between glucose and fructose in both hives. In the experiment with the incubator we confirmed different metabolism between healthy and unhealthy bees, although this was not confirmed statistically.