Abstract Background In the PrefHer study, subcutaneous administration of trastuzumab was preferred over intravenous administration (iv). In 2014 our hospital approved subcutaneous (sc) trastuzumab for use in patients with early or metastatic Her 2 positive breast cancer. The aim of this study was to evaluate patients (pts) and nurses´s preferences in our institution. Methods Patients with Her2 postive breast cancer and nurses who had received or administered both sc and iv trastuzumab were interviewed to evaluate their preference. Preference for sc was compared with a linear chi squared test. Results 55 pts were interviewed. Median age was 53 years (30-83). 30 patients in adjuvant/neoad setting and 25 pts in the palliative setting. 41 pts (74.5%) preferred sc 95% CI (63-86) , 3 pts (5.5%) preferred iv 95% CI (-0.5-11.5) and 11 pts (20%) did not have preference 95% CI (9.4-20%) p< 0.0001. 72% of pts considered that sc trastuzumab was more convenient (p<0.0001). 11 nurses experienced with both iv and sc trastuzumab administration answered the questionnaire. Median age 41 years (30-55). 10/11 nurses preferred sc administration, 1/10 indicated no preference. All nurses considered that sc was the most convenient administration method for the patients and is highly recommended. The main reason for patients and nurses preference was that sc administration saved time. Conclusion Patients and nurses prefer s.c over iv trastuzumab. Our results are consistent with PrefHer study. Incorporation of sc trastuzumab could improve quality of care in patients with Breast Cancer Her 2 positive. Citation Format: Castillo-Fernandez O, Cabreja A, Arauz E, Bellido D, Lim M, Lopez R, Montano L. Do patients and nurses outside clinical trial prefer subcutaneous trastuzumab over conventional intravenous infusion? Instituto Oncologico Nacional experience [abstract]. In: Proceedings of the 2016 San Antonio Breast Cancer Symposium; 2016 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2017;77(4 Suppl):Abstract nr P5-11-16.