ABSTRAKAngka kenaikan pasien Covid-19 khususnya varian omicron mulai menunjukkan kenaikan signifikan mulai awal tahun 2022 ini. Gejala varian omicron yang hampir mirip dengan influenza dan faringitis menyebabkan masyarakat cukup sulit membedakan apakah terkena Covid-19 varian omicron atau hanya influenza atau faringitis. Penelitian ini menggunakan metode sistem pakar Certainty Factor untuk memberikan kepastian dari sebuah ketidakpastian akan gejala Covid-19 varian omicron ini. Dari hasil pengujian sampel dengan gejala demam, kelelahan, pegal-pegal, sakit kepala, sakit menelan dan pilek, diperoleh nilai persentase keyakinan penyakit Covid-19 yaitu 68,94%, penyakit influenza sebesar 56,32% dan penyakit faringitis sebesar 49,17%. Nilai persentase keyakinan terbesar dari masing-masing penyakit adalah 68,94% yaitu kemungkinan pasien menderita penyakit Covid-19 varian omicron.Kata kunci: omicron, influenza, faringitis, certainty factor, sistem pakarABSTRACTThe increase in the number of Covid-19 patients, especially the omicron variant, began to show a significant increase starting in early 2022. The symptoms of the omicron variant, which are almost similar to influenza and pharyngitis, make it quite difficult for people to distinguish whether they have the omicron variant of Covid-19 or just influenza or pharyngitis. This study uses the Certainty Factor expert system method to provide certainty from an uncertainty about the symptoms of this omicron variant of Covid-19. From the results obtained from  several testing samples with symptoms of fever, fatigue, aches, headaches, swallowing and runny nose, the confidence value for Covid-19 disease is 68.94%, for influenza disease is 56.32 % and for pharyngitis is 49.17%. The largest confidence value for each disease is 68.94%, which is the possibility of the patient suffering from the omicron variant of Covid-19 disease.Keywords: omicron, influenza, pharyngitis, certainty factor, expert system