This study was conducted to determine length-weight (LWR) and length-length (LLR) relationships for 10 fish species caught by electrofishing between August 2005 and July 2006 in Kirmir Stream and its tributaries (Suveri and Ilhan Stream) of Sakarya River, Central Anatolia, Turkey. The length-weight relationships (LWR) exponent b values ranged from 1.940 in Cobitis taenia (Linnaeus, 1758) to 3.377 in Gobio gobio (Linnaeus, 1758). The b values of the length-weight relationships (LWR) for Capoeta sieboldi (Steindachner, 1864) and Alburnus orontis (Sauvage, 1882) were close to 3 indicating the isometric growth (b=3, p<0.05). The b values of the length-weight relationships (LWR) exhibited a positive allometric growth in Squalius cephalus, Barbus plebejus (Heckel, 1843), and Gobio gobio (Linnaeus, 1758) (b>3, p<0.05), versus a negative allometric growth in Capoeta baliki (Heckel 1843), Alburnoides bipunctatus (Bloch, 1782), Chondrostoma regium (Heckel, 1843), Cobitis taenia (Linnaeus, 1758) and Oxynoemacheilus angorae (Steindachner, 1897) (b<3, p<0.05). All the length-weight relationships (LWR) and length-length relationships (LLR) were statistically significant (r2>0.550, p<0.05 and r2>0.754, p<0.05).