The CSIRO Global Atmospheric Sampling Laboratory (GASLAB) Flask Sampling Network archive for the carbon 13 isotope (C13) of atmospheric trace gas carbon dioxide (CO2) concentrations. GASLAB principally analyzes air samples that have been captured at eleven fixed geographic sites and one moving (aircraft over bass strait and Cape Grim), but also includes other sites at various locations globally on a less regular or as needed basis. The CO2C13 measurements are made by concentrating the CO2 from the air sample utilising a 3 step automated cryogenic trapping system connected to a dual inlet stable isotope ratio mass spectrometer (Finnigan MAT252) for analysis. The CO2 and N2O gas chromatography concentrations data for the sample are used for ion corrections on the stable isotope measurements. Alternatively the Cape Grim in situ air sample (cia) which has already had the trapping process applied to it on site, uses the data from the Cape Grim in situ CO2 analyser, with the N2O concentration determined by interpolation from the CSIRO global flask network data. There are 6 differant types of flask that are used to store and transport air samples from site and in the labratory:(i) glass 0.5 litre ("G050"), (ii) glass 5.0 litre ("G500"), (iii) glass 0.8 litre ("G080"), (iv) electropolished stainless steel 1.6 litre "Sirocans" ("S160"), (v) glass 2.0 litre, 1 stopcopck ("F", "FF", "FA", "FE", "EP", ALT"), (vi) glass 2.0 litre, 2 stopcocks(“M1”, “S”, “P2”, “TEMP”). Files containing a single species value for each sample are denoted by a filename of the form (XXX_XXXX_event.XXX), for the geographically fixed sites data is also provided in the form of monthly means (e.g. XXX_XXXX_mm.XXX) with all files being in ascii format.