This thesis presents a study on the behaviour of connections using screws in cold-formed steel structures. The first part of the thesis studies the behaviour of the screw connectors using simple connection tests and Finite Element (FE) modelling. Specimens were assembled by using 2 or 3 screws connecting two cold-reduced sheet steels with various grades and thicknesses. Two types of limit states were investigated: (i) screw shear failure and (ii) bearing and tilting failure. A set of revised design equations for strength of screwed connections in bearing and tilting is proposed. A reliability analysis is performed using the proposed equations, which allow for an improvement in the capacity reduction factor in current design standards. Furthermore, an FE model, which contains fracture characteristics of both the screws and the sheet steels, is developed to give better understanding of the screw behaviour with respect to different limit states. In the second stage of the research, a dual-actuator test apparatus was set up in order to test shear connections from cold-formed steel channels to hollow sections. Each connection contained an angle cleat and two screws. Different amount of shear force and connection rotation to transfer into the connection in each test. Two limit states involving failure of the screws and failure of the sheets were investigated. Finally, an analytical model for the connection is developed using the relation between bearing force and deformation of individual screws from the first stage of the thesis. An FE model is also developed, which demonstrates how to apply actual geometry of the screws into a simulation at a structure scale. It is concluded that a simple connection carrying shear with bearing and tilting failure mode has better strength conserving capability when dealing with high rotation compared with a connection with shear fracture of the screws.