Dissolved organic carbon (DOC) is a general description of the organic material dissolved in water. Organic carbon occurs as the result of decomposition of plant or animal material. Organic carbon present in soil or water bodies may then dissolve when contacted by water. This dissolved organic carbon moves with both surface water and ground water. The concentration of dissolved organic carbon (DOC) in surface waters has implications for both carbon availability in downstream lakes and for water supplies, and is an important consideration in the formulation of regional and global carbon budgets. This dataset comprises high frequency fluorescence CDOM (chromophoric dissolved organic matter) data, which is a good proxy for DOC concentration. The data were collected using in-situ sensors (Seapoint CDOM UV fluorometers, www.seapoint.com/suvf.htm, Seapoint, Exeter, NH 03833, USA), deployed in two locations in the Burrishoole catchment, the Glenamong river and Lough Feeagh, Co. Mayo, Ireland from 2004 to 2011. Hourly mean temperature corrected (to 20 °C) fluorescence data were converted to estimated DOC concentration (mg DOC L-1) based on calibration equations established using measured DOC data and CDOM data from 2004 to 2011. These estimated DOC values are also included in this dataset. More information can be obtained from burrishooleLTER@marine.ie None Suggested Citation: Dillane, Mary; Jennings, Eleanor; Ryder, Elizabeth; Nic Aonghusa, Caitriona; de Eyto, Elvira; Cooney, Joseph; Hughes, Pat; Murphy, Michael; Nixon, Pat; Sweeney, David; Rouen, Martin. (2020) Hourly measurements of chromophoric dissolved organic matter (CDOM) and estimated dissolved organic carbon (DOC) from the Glenamong River (2004, 2006, 2010) and Lough Feeagh (2010-2011), Burrishoole catchment, Co. Mayo. Marine Institute, Ireland. doi:10/d6m8.