We investigated in human B lymphocytes the interaction of antigen receptor (BCR) and P2X7 receptor activation on intracellular Ca²⁺ concentration ([Ca²⁺]_i) signalling and on nuclear translocation of the transcription factor NFAT. The activator of P2X7 receptors, ATP, is released during inflammatory processes or tissue damage. In B lymphocytes ligation of BCR induces a biphasic [Ca²⁺]_i response. The activation of the P2X7 receptor raises a cationic ion current which carries sodium, calcium and potassium. The extent of the accompanying calcium influx increases the global intracellular calcium concentration which is strongly dependent on the degree of the depolarisation of the cell membrane. The spatiotemporal pattern of the intracellular calcium concentration is a critical trigger for the activation and translocation of NFATc1 to the nucleus, a signal that plays a key role in the activation of many early immune response genes. We measured the interaction of BCR and P2X7 receptor activation regarding the Ca²⁺ signal by FACS and single cell imaging, changes of the membrane potential by FACS and the translocation of NFATc1 from cytoplasma to the nucleus using immunfluorescence and confocal microscopy. We found that NFATc1 nuclear translocation induced by BCR activation is influenced by ATP. At free ATP concentrations above 90 mM the sustained calcium influx induced by BCR ligation is diminished by depolarisation of the B cells. We therefore conclude that P2X7-receptor activation impairs the BCR-induced NFATc1 translocation which may alter the immune response of B lymphocytes.