Thrombolysis in myocardial infarction (TIMI) is a prognostic score developed for managing the high risk of cardiac events immediately after unstable angina and non-ST elevation myocardial infarction (UA/NSTEMI). In Asian populations that have a higher rate of bleeding complications, data about TIMI score are lacking. Using a Japanese multicenter registry, we investigated the impact of utilizing TIMI score in UA/NSTEMI patients, focusing on bleeding complications. The TIMI score was calculated for 587 patients who underwent percutaneous coronary intervention (PCI) for UA/NSTEMI (2008–2010). They were classified into low-risk (TIMI score 0–2, N = 268, 45.6 %), intermediate-risk (TIMI score 3–4, N = 264, 45.0 %) and high-risk (TIMI score 5–7, N = 55, 9.4 %) groups; patient characteristics for each group were statistically analyzed. The patients in the higher TIMI score group were older (p < 0.001), had lower GFR (p = 0.021) and hemoglobin level after PCI (p < 0.001), and severe coronary disease pattern (p = 0.014 and p = 0.023, respectively, for left main and three-vessel disease). The TIMI score was significantly associated with requirement of blood transfusion (low-risk, moderate-risk, and high-risk groups: 1.1, 4.2, and 7.3 %, respectively; p = 0.021), and the incidence of access site bleeding (1.1, 2.7, and 5.5 %, p = 0.112). The TIMI score might aid in subjectively quantifying the risk of in-hospital complication rates such as access site bleeding.