Updated project metadata. We quantified proteins in the model cyanobacterium Synechocystis sp. PCC 6803 given the general importance of cyanobacteria for global photosynthesis, for synthetic biology and biotechnology research, and their ancestral relationship to the chloroplasts of plants. Four mass spectrometry methods were used to quantify 97 cellular components involved in the biosynthesis of chlorophyll, carotenoid and bilin pigments, membrane assembly, the light reactions of photosynthesis, fixation of carbon dioxide and nitrogen, and hydrogen and sulfur metabolism. One quantification method was calibrated with artificial 15N-labelled proteins comprising concatenated proteotypic tryptic peptides and the other three methods were label-free (DDA-iBAQ, DDA-Top3, DIA-Top3) calibrated with the Sigma UPS2 standard protein mixture. As expected, the quantification methods gave individual distributions of abundance levels for each target protein that, for statistical validity, were not combined into single central tendency and variation metrics. Instead, overlapping distributions were merged to provide consensus abundance ranges. Quantification, expressed as copy numbers per cell (cpc), spanned four orders of magnitude, representing the complete abundance range from <1000 to >100,000 cpc of the proteins representing the complexes and pathways that were the focus of this study.