We analyzed the gene expression changes in the wild type and the delta kaiAB1C1 mutant at six time points after a 12 hours dark incubation. RNA-Seq provides a much higher senisitivity and resolution in comparison to previously performed micro array experiments. We aim to get a better understanding how the circadian oscillator which is encoded by the kaiABC genes regulates the overall gene expression in Synechocystis sp. PCC 6803. Overall design: Cells were harvested during the first dark period and the following light period. Time is given as zeitgeber time (ZT) with ZT 0.5 being the first sample during dark incubation 0.5 h after the shift from light to dark. Two biological replicates were harvested at ZT={0.5, 5.5, 11.5, 12.5, 17.5, 23.5} and total RNA was isolated