The research covered in this thesis was carried out to test the hypothesis that genetic differences exist between the populations of North and South Pembrokeshire, due to their different cultural histories; and to the cultural and linguistic divide which exists between them. For convenience the work has been divided into four sections. Section One considers the history and geography of the county, going on to look in detail at parish records, Pembrokeshire surnames and present-day demographic data. The latter part of this Section considers previous genetic studies made in Wales, and, finally, the partitioning parameters used in the genetic surveys are discussed. Section Two covers the dermatoglyphic survey, initially describing the methodology used and going on to discuss and interpret the results obtained. Univariate and multivariate statistical techniques have been used. Section Three considers the skin pigmentation study and includes a brief description of the methodology and discusses the results and the genetic and environmental effects on skin colour. Section Four covers the serology survey. The methodology is described briefly, and the Pembrokeshire results are discussed and compared with the results for other European populations.