This codebook details how aid events that are available from AidData and other donor sources can be assigned latitude and longitude coordinates, i.e. be geo-referenced, under the UCDP/AidData coding rules. The rules are derived from the UCDP Geo-referenced Event Dataset (GED) Codebook version 1.0 (Sundberg et al., 2010) which covers the geo-referencing of violent events. The system has been adapted and complemented by additional rules to enable the coding of aid projects rather than battles. The UCDP GED is used as a starting point as it permits us to identify and record a hierarchy of locations differentiated by various precision scores. Sources vary in the precision that locations are reported; sometimes the exact location is named and in other instances the general area is reported. Following UCDP, the system of geo-referencing used by UCDP/AidData can therefore cope with coordinates at four main levels, ranging from point locations, through two administrative divisions, to the country level. Eight precision categories are connected to the coordinates in order for researchers to select subsets of the data set that contain different levels of precision. The main objective is to record all locations to which aid dollars are committed or distributed. Locations that benefit indirectly are not coded, unless the geographic locations of the indirect areas are significant enough to be clearly spelled out in project documents.