Abstrak. Tomat (Solanum lycopersicum) merupakan salah satu komoditas pertanian yang ditanam secara luas di seluruh dunia, termasuk di Indonesia, karena memiliki rasa yang khas dan enak, juga memiliki nilai gizi seperti sumber vitamin A dan C yang sangat baik. Produksi tomat mengalami penurunan setiap tahun, salah satunya diakibatkan oleh organisme penganggu tanaman (OPT) yaitu patogen Fusarium oxysporum sehingga perlu dilakukan pengendalian hayati yaitu menggunakan Trichoderma harzianum dalam bentuk formulasi pelet yang praktis, efektif, dan efesien. Penelitian ini menggunakan Rancangan Acak Lengkap (RAL) non faktorial yang terdiri dari 6 perlakuan dengan 3 ulangan, setiap perlakuan terdiri dari 10 unit bibit tomat. Penelitian ini terdiri dari 6 perlakuan yaitu perlakuan A (masa simpan pelet T. harzianum 4 minggu), B (masa simpan pelet T. harzianum 3 minggu), C (masa simpan pelet T. harzianum 2 minggu), D (masa simpan pelet T. harzianum 1 minggu), E (masa simpan pelet T. harzianum 0 minggu), F (tanpa perlakuan pelet T. harzianum). Peubah yang diamati yaitu pre-emergence damping off, post-emergence damping off, masa inkubasi, persentase tanaman layu, tinggi tanaman, dan jumlah daun. Hasil penelitian menunjukkan bahwa pelet T. harzianum yang disimpan 4 minggu efektif dalam menghambat perkembangan penyakit layu fusarium seperti menunda masa inkubasi sampai 7 HSI, menekan pre-emergence damping off sampai 90%, post-emergence damping off 92,95%, serta mampu meningkatkan tinggi tanaman sampai 19,63 cm dan meningkatkan jumlah daun rata-rata 7 helai pada 35 HSI. (Storing Period of Trichoderma harzianum Pellets and its ability to Inhibit the development of Fusarium Wilt Disease on Tomato Seeds)Abstract. Tomato (Solanum lycopersicum) is one of the most widely grown commodities in the world, including Indonesia. It has a distinctively good taste and many nutritional value such as vitamin A and C. However, tomato production has decreased every year. One of the main cause is the attacks by pathogens, named Fusarium oxysporum. A Biological control is necessary and the use of Trichoderma harzianum in the form of pellets is recommended because of its effectiveness, efficiency and practical use. This research used a Completely Randomized Design (RAL) non-factorial consisted of 6 treatments with 3 replications, each treatment consisted of 10 units of tomato seedlings. The 6 treatments are named as treatment A (T. harzianum pellet saving 4 weeks), B (T. harzianum pellet saving period 3 weeks), C (shelf life of 2 weeks T. harzianum pellet), D (shelf life of pellet T harzianum 1 week), E (shelf life of pellet T. harzianum 0 weeks), and F (without T. harzianum pellet treatment). The variables observed in this study are pre-emergence damping off, post-emergence damping off, incubation period, the percentage of wilted plants, plant height, and the number of leaves. The results showed that pellets of T. harzianum stored 4 weeks effectively inhibiting the development of fusarium wilt disease such as delaying incubation period up to 7 HSI (Days After Incubation), suppressing the pre-emergence damping off up to 90% and post-emergence damping off to 92.95%, also able to increase the plant height up to 19.63 cm and increase the average leaf number of 7 strands at 35 HSI.