Aim Outpatient parenteral antimicrobial therapy (OPAT) is an option in patients who require parenteral antimicrobial administration and are clinically well enough for hospital discharge. This is an update of the Irish National OPAT guidelines which were last reviewed in 2011. Methods The guideline was devised through a collaborative process with the national OPAT Working Group and a review of the literature. It is intended for clinicians who prescribe any intravenous (IV) antimicrobials outside of the inpatient setting in the Republic of Ireland. Results Patient care while on OPAT should be provided by a designated OPAT service, with clear managerial and clinical governance lines of responsibility. It should be conducted using a team approach with a clinical lead on each site either as an infection specialist, or a general medical physician with infection specialist input and an OPAT nurse. An antimicrobial pharmacist is also desirable. Several factors must be considered when assessing patient's suitability for OPAT including exclusion criteria, infection-specific factors, and patient specific factors such as physical, social and logistic criteria. Conclusion This updated guideline advocates a more individualised OPAT approach, with the recognition that specific antimicrobials and/or specific delivery models may be more appropriate for certain patient groups. Full guidelines are available through www.opat.ie.