Complexity and Strategies for parametric design in architecture. An application of practice led research. Nowadays a new specialist design role is emerging in the construction industry. The primary task related to this role is focused on the control, development and sharing of geometric information with members of the design team in order to develop a design solution. Individuals engaged in this role can be described as a parametric designers. Parametric design involves the exploration of multiple solutions to architectural design problems using parametric models. In the past these models have been defined by computer programs, now commercially available parametric software provides a simpler means of creating these models. It is anticipated that the emergence of parametric designers will spread and a deeper understanding of the role is required. This thesis is aimed at establishing an understanding of the tasks related to this new specialism and to develop a set of considerations that should be made when undertaking these tasks. The position of the parametric designer in architectural practice presents new opportunities in the design process this thesis also aims to capture these. Through research and design, this thesis seeks to answer two questions: what is parametric design and how can it benefit the field of architecture? Looking at historical and present-day sources, the evolution of computer aided design has been drawn out leading to the emergence of parametric design. An explanation and analysis of parametric tools, including a series of case studies, has been conducted to show how these tools are presently being utilized by designers.