Abstract Background Lithium is a psychotropic medication used for the treatment of bipolar affective disorder and augmentation for treatment resistant depression. Lithium monitoring is essential due to the narrow therapeutic range of serum lithium and the potential for toxicity. Other medications with similar risk profiles, such as warfarin, have established monitoring programmes. Older adults receiving lithium therapy are at an increased risk of adverse events, given the prevalence of medical co-morbidities and changing pharmacokinetics. The authors of this audit identified the lack of formalized lithium monitoring programme in the Mental Health Service for Older Persons (MHSOP). The aim of this audit to compare monitoring practices in the MHSOP against the current gold standard Irish Medication Safety Network (IMSN) for Prescribing and Monitoring of Lithium Therapy. Methods A survey of all community medical charts identifying patients attending the service receiving lithium therapy was completed. Data collected pertained to diagnosis, treating consultant, lithium dose, if the patient received educational material, compliance with ECG and blood monitoring. Results The MHSOP active case load was 682 patients, 14 patients were prescribed lithium therapy. Cycle 1 of the audit demonstrated poor compliance of lithium monitoring against the gold standard. A lithium pack was inserted in patient files to prompt all clinicians to follow the recommended standardized monitoring of lithium therapy as per the IMSN guidelines. In cycle 2 of the audit there was an improvement in recording blood monitoring across the patient group. Conclusion The audit demonstrated improvement in compliance with international guidelines following the intervention. It was recommended that a formalized Lithium Clinic was a needed resource for the MHSOP. The lithium monitoring pack will continue to be added to clinical files, included in Non-Hospital Consultant (NCHD) induction and multi - disciplinary teaching sessions. It is proposed that the audit be repeated in one year to longitudinally assess compliance.