Generally, structural design and assessment documents are continually improved upon. The most common challenges that often arise with the introduction of a new document are its application and interpretation. This paper presents the results of evaluation of the use of the Eurocodes for bridge fatigue assessment of existing steel bridges designed to the specifications of older standards. The rate of fatigue damage in truss components of a Pratt through truss steel bridge is evaluated using the nominal stress approach. Comparison is made between the results obtained using the increased loadings of the BS Eurocodes as against using the old BS 5400. The results show that using the new code for assessment is beneficial only when its loadings are not directly employed in the assessment of in-service bridges, as the rate of damage to member details can be 150 higher when the loadings of the new code are directly employed. © 2016 Taylor & Francis Group, London.