Introduction. Dental Composite consists of matrix resin, coupling agents, filler, and other supportive materials, its filler is inorganic materials [1]. Their characteristics are non-biodegradable, non-renewable, non-recyclable that contained in composite resin [2]. Natural fiber can be used as substitute for inorganic filler. The most potential natural fiber such as sisal fiber (Agave sisalana) [3]. Sisal fibers are hard and strong fibers derived from sisal plants and can be used as mechanical amplifiers to the matrix resin [3]. This study has manufactured composite resins with sisal that sized nano as their filler and we called nanosisal dental composite. Nanosisal filler volume was recomended at 60% [4]. Tensile strength can predict bond strength reliably for material endurance clinically [5]. This study aimed to determine the difference of tensile strength between nanosisal composite 60% filler with nanofiller dental restorative composite. Experimental. Sisal fiber converted into nano-sized sisal, labeled as nanosisal. Nanosisal mixed with Bisphenol A glycerolate dimethacrylate (Bis-GMA, Sigma Aldrich), Diurethane dimethacrylate (UDMA, Sigma Aldrich), Triethylene glycol Dimethacrylate (TEGDMA, Sigma Aldrich), Champhorquinone (Sigma Aldrich). Nanofiller composite (Z350 XT 3M ESPE) was utilized as control. We used 10 cone-sized sample (4 x 4 x 2 mm). They divided into 2 groups. Nanosisal composite 60% labeled as group A, nanofiller composite labeled as group B. Extracted premolar teeth were prepared to class V (G. V. Black classifications), then their were filled using samples with total etch adhesive system (3M ESPE). Samples were tested for tensile strength using a Universal Testing Machine. Data was analyzed by Independent Sample T-Test. Results and Discussion. The mean of tensile strength of nanosisal 60% filler composite resin was 4.39 MPa, and nanofiller composite resin was 1.23 MPa. There was a significant difference in data analysis (p = 0.004; p < 0.05). It was caused by nanosisal composite has stronger bond formed between nanosisal fiber, matrix resin and adhesive due to chemical bond of OH groups [3]. Conclusions. The result showed that nanosisal 60% filler composite resin has higher tensile strength rather than nanofiller composite resin.