BertiniLab: a MATLAB interface for solving systems of polynomial equations. A MATLAB interface to the numerical homotopy continuation package Bertini is described. Bertini solves systems of polynomial equations. BertiniLab can be used to create input files for Bertini, run Bertini and process the solutions. All features of Bertini 1.5 are supported. The user can define the system of equations using a MATLAB numerical function, and vector and matrix operations are allowed. An object-oriented design allows the user to separate the statement of the problem from the details of the solution; the user can create subclasses to provide shortcuts or to tailor BertiniLab to a specific kind of problem. A complete example of an application to ferromagnetism is presented.