In the generation of intense magnetic fields using copper wire‐wound solenoids an upper field limit is often imposed by Lorentz forces in the conductor. The use of materials such as 2% Be‐Cu alloy increases the maximum stress permitted fields, but their high resistivity leads to an unfavourable energy limitation. The use of copper‐clad steel however enables the roles of conductor and strengthener to be separated and by varying the copper/steel ratio to be almost independently controlled. Using a given energy source the energy limitation is determined taking Joule heating into account by an iterative computer technique. The stress limitation is determined1taking the Youngs moduli of copper, steel and insulation into account. Calculations have been made using a range of energy sources and pulse lengths of 1 ms and 10 ms. By varying the copper/steel ratio it is possible to design an optimum coil for which the energy and stress limitations coincide. It is found that in most cases, fields higher than those possible with pure copper wire are obtainable, with increases in maximum field of up to 30%. Practical examples of such coils will be presented and the problems associated with winding copper steel composite coils will be discussed. In addition it will be shown that the steel component has a well defined effect on the field profile of the solenoid at low magnetic fields.