Abstract. Lean management is a concept that is applied to increase efficiency and prevent waste in the production process. Sidoarjo Government Hospital has implemented lean management through Kaizen activities since 2016. Kaizen Festivals were held in 2016 and 2018. However, for four years, there has been no evaluation of the sustainability of kaizen activities.This study aimed to evaluate the sustainability of kaizen activities and identify the influencing factors. Quantitative contingency coefficient analysis was carried out on survey responses. The research was conducted at Sidoarjo Government Hospital involving 20 respondents from 22 total population of the kaizen unit team. Data collection was carried out through a questionnaire filled out by representatives of the kaizen unit team who participated in the Kaizen Festival from 2016 to 2018.The results showed that all 20 respondents participated in the Kaizen Festival in 2016 and 2018, but only 13 (65%) had kaizen activities in 2017. The three-year sustainability of kaizen activities was 85%, the two-year sustainability of kaizen activities was 40%, and the one-year sustainability of kaizen activities was 75%. The factors affecting the sustainability of kaizen activities were the other stakeholder support (r 0.707, p <0.05), the benefits (r 0.622, p <0.05), and the regulatory changes (r 0.519, p <0.05). Meanwhile, the role of the unit leader (p 0.531-0.715), staff support (p 0.335-0.666), and the supervision of top hospital management (p 0.188-0.718) did not have a statistical correlation with the sustainability of kaizen activities. Thus, the most important factor affecting the sustainability of kaizen activities was the other stakeholder support. All units implemented kaizen activities because of the encouragement of the kaizen festival.