The goal was to measure and model the soil carbon stocks and stock changes in a representative number of Irish soils. An intensive field and laboratory campaign was carried out over the period 2006–2007 on 71 sites throughout Ireland. Most of these were a subset of the National Soil Database (NSD) sites. Each site was sampled at several increments over a depth of 50 cm for soil carbon concentration, bulk density, texture and soil elemental properties. In addition, water samples were collected at 55 stream sites close to the soil sampling sites on seven occasions from October 2006 to October 2007, and analysed for dissolved organic carbon (DOC). Regression equations were generated to explain the relationship between soil organic carbon (SOC) concentrations and loss on ignition (LOI) data.