Thermoluminescent (TL) dosimeters are routinely used to monitor absorbed doses in many kinds of radiation fields which contain photons, electrons and neutrons. However, TLDs are mainly calibrated to photon sources. We studied the response of TLDs to complex secondary fields arising during the operation of high-energy accelerators (e.g. the Large Hadron Collider (LHC) at CERN). The experiments were conducted at the CERN–EU high-energy reference field facility (CERF). Six different LiF-based TLDs (MTS-N, MTS-7, MTS-6, MCP-N, MCP-7, MCP-6) were exposed to various secondary CERF's fields (both for high and low doses), by placing them at various positions: at the target and concrete top and side positions. For the experiment at the target the corresponding Monte Carlo calculations were also carried out using the FLUKA transport code and compared with experimental results. In addition, alanine dosimeters were used as an independent reference. The results show that TLDs are well suited for monitoring radiation fields around the LHC. Nevertheless, further investigations are required, some of which are in progress.