An all-case post marketing surveillance (PMS) of baricitinib (Bari), that started in Sep 2017, collects safety and effectiveness for the first 24 wks of treatment and continues to collect serious adverse events (SAEs) for 3 yrs.To evaluate Bari safety in RA patients (pt) in clinical practice.We report pt baseline demographics and adverse events (AEs) up to 24 wks for pts whose case report files for 24-wk data were completed as of Jun 2020.Data from 3445 pts were analyzed (females=80%, mean age=64yr, mean RA duration 12yr). Bari dose regimen was as follows: 4mg, 60%, 2mg, 27%, 4mg→2mg, 5%, 2mg→4mg, 5%, and others, 2%. Concomitant use of MTX and glucocorticoid was 65% and 48%, respectively. 74% continued treatment for 24 wks. AE and SAE were recognized in 887 (26%) and 122 pts (4%), respectively. 6 pts died of pneumonia, aspiration pneumonia, bacterial pneumonia, cerebral infarction/ILD/aspiration pneumonia, adenocarcinoma, and colorectal cancer. Major AEs were as follows: herpes zoster=3%, liver dysfunction=3%, serious infection=1%, anemia=1%, hyperlipidemia=1%, malignancy=0.3%, interstitial pneumonia=0.2%, MACE=0.1%, and VTE=0.1%.Data do not show new safety concerns and encourage guideline-compliant use of Bari.Takao Fujii Speakers bureau: Chugai Pharmaceutical Co. Ltd.; Eisai Co. Ltd; Eli Lilly Japan K.K.; Janssen Pharmaceutical K.K.; Ono Pharmaceutical Co. Ltd., Consultant of: Asahikasei Pharma Corp, Grant/research support from: Asahikasei Pharma Corp; AbbVie Japan GK; Chugai Pharmaceutical Co. Ltd., Eisai Co. Ltd; Eli Lilly Japan K.K.; Mitsubishi-Tanabe Pharma Co.; Ono Pharmaceutical Co., Ltd., Tatsuya Atsumi Speakers bureau: AbbVie Japan GK; Astellas Pharma Inc.; Bristol-Myers Squibb Co. Ltd; Chugai Pharmaceutical Co. Ltd.; Daiichi Sankyo Co. Ltd.; Eisai Co. Ltd.; Eli Lilly Japan K.K.; Mitsubishi Tanabe Pharma Co.; Pfizer Japan Inc.; Takeda Pharmaceutical Co. Ltd., UCB Japan Co. Ltd., Consultant of: AbbVie Japan GK; AstraZeneca plc.; Boehringer Ingelheim Co. Ltd.; Medical & Biological Laboratories Co. Ltd.; Novartis Pharma K.K.; Ono Pharmaceutical Co. Ltd.; Pfizer Japan Inc., Grant/research support from: Astellas Pharma Inc., Alexion Inc.; Chugai Pharmaceutical Co. Ltd., Daiichi Sankyo Co. Ltd., Mitsubishi Tanabe Pharma Co., Otsuka Pharmaceutical Co., Ltd.Pfizer Japan Inc.; Takeda Pharmaceutical Co. Ltd., Nami Okamoto Speakers bureau: AbbVie Japan GK; Asahikasei Pharma Co.; AYUMI Pharmaceutical Co.Eisai Co. Ltd; Bristol-Myers Squibb Co. Ltd.; Eli Lilly Japan K.K.; Mitsubishi-Tanabe Pharma Co.; Pfizer Japan Inc.Sanofi K.K.; Chugai Pharmaceutical Co. Ltd.; Novartis Pharma Co.; Teijin Pharma Ltd.; Torii Pharmaceutical Co., Ltd., Nobunori Takahashi Speakers bureau: AbbVie Japan GK; Eisai Co. Ltd.; Mitsubishi Tanabe Pharma Co.; Pfizer Japan Inc.; Chugai Pharmaceutical Co., Ltd.; Eli Lilly Japan K.K.; Janssen Pharmaceutical K.K.; UCB Japan Co. Ltd.; Astellas Pharma Inc.; Bristol Myers Squibb Co. Ltd., Grant/research support from: Bristol Myers Squibb Co. Ltd., Naoto Tamura Speakers bureau: AbbVie Japan GK; Bristol Myers Squibb Co. Ltd.; Chugai Pharmaceutical Co. Ltd.; Eisai Co. Ltd.; Eli Lilly Japan K.K.; Glaxo Smith Kline K.K.; Janssen Pharmaceutical K.K.; Mitsubishi-Tanabe Pharma Co.; Novartis Pharma Co., Atsuo Nakajima: None declared, Ayako Nakajima Speakers bureau: AbbVie Japan GK; Actelion Pharmaceuticals Japan Ltd., Asahi Kasei Pharma Co., Astellas Pharma Inc., Ayumi Pharmaceutical Co., Bristol Myers Squibb Co., Ltd.,Chugai Pharmaceutical Co., Ltd., Eisai Co., Ltd., Eli Lilly Japan K.K., Glaxo Smith Kline K.K., Hisamitsu Pharmaceutical Co. Inc., Kyorin Pharmaceutical Co. Ltd., Mitsubishi Tanabe Pharma Co., Otsuka Pharmaceutical Co. Ltd., Pfizer Japan Inc., Teijin Pharma Ltd., Grant/research support from: Chugai Pharmaceutical Co., Ltd., Mitsubishi Tanabe Pharma Co., Pfizer Japan Inc., Hiroaki Matsuno Speakers bureau: Chugai Pharmaceutical Co., Ltd., Daiichi Sankyo Co., Ltd., Eli Lilly Japan K.K., Consultant of: Mochida Pharmaceutical Co., Ltd., Grant/research support from: Astellas Pharma Inc., Eli Lilly Japan K.K.; Janssen Pharmaceutical K.K, Naoto Tsujimoto Shareholder of: Eli Lilly, Employee of: Eli Lilly Japan K.K., Atsushi Nishikawa Shareholder of: Eli Lilly, Employee of: Eli Lilly Japan K.K., Taeko Ishii Shareholder of: Eli Lilly, Employee of: Eli Lilly Japan K.K., Tsutomu Takeuchi Speakers bureau: AbbVie Japan GK, Ayumi Pharmaceutical Co., Bristol Myers Squibb Co., Ltd., Chugai Pharmaceutical Co, Ltd. Daiichi Sankyo Co., Ltd. Eisai Co., Ltd. Eli Lilly Japan K.K.; Gilead Sciences, Inc. Janssen Pharmaceutical K.K.; Mitsubishi-Tanabe Pharma Co.; Novartis Pharma Co.; Pfizer Japan Inc.; Sanofi K.K.; UCB Japan Co., Ltd., Consultant of: AbbVie Japan GK, Astellas Pharma, Inc.; Chugai Pharmaceutical Co, Ltd.; Eli Lilly Japan K.K.; Eisai Co., Ltd.; Gilead Sciences, Inc.; Janssen Pharmaceutical K.K.; Mitsubishi-Tanabe Pharma Corp., Pfizer Japan Inc., Grant/research support from: AbbVie Japan GK, Asahikasei Pharma Corp., Chugai Pharmaceutical Co, Ltd., DNA Chip Research Inc.; Eisai Co., Ltd., Eli Lilly Japan K.K.; Mitsubishi-Tanabe Pharma Corp., UCB Japan Co., Ltd., Masataka Kuwana Speakers bureau: AbbVie Japan GK, Astellas Pharma Inc., Asahi Kasei Pharma Co., Boehringer-Ingelheim, Chugai Pharmaceutical Co., Ltd., Eisai Co., Ltd., Janssen Pharmaceutical K.K., Medical &Biological Laboratories Co., Ltd.; Mitsubishi Tanabe Pharma Co.; Mochida Pharmaceutical Co., Ltd., Nippon Shinyaku Co., Ltd.; Ono Pharmaceutical Co., Ltd.; Pfizer Japan Inc., Consultant of: Boehringer-Ingelheim, Chugai Pharmaceutical Co., Ltd., Corbus Pharmaceuticals Holdings, Inc.; Medical &Biological Laboratories Co., Ltd.; Mochida Pharmaceutical Co., Ltd., Grant/research support from: Boehringer-Ingelheim, Chugai Pharmaceutical Co., Ltd., Eisai Co., Ltd., Medical &Biological Laboratories Co., Ltd; Mitsubishi Tanabe Pharma Co., Ono Pharmaceutical Co., Ltd., Michiaki Takagi Speakers bureau: Yes, but sponsored lectures without COI in the academic meetings, only.