This study exhibits relationships between length-weight and length-length for 21 fish species caught in Izmir Bay. Coefficients a and b for the length-weight relationships (LWRs) and length-length relationships (LLRs) were calculated with W=aLb formulae and as equations of TL=a+bFL and TL=a+bSL respectively. Equations of length-length for converting standard length and fork length into total length and vice versa were proven linear. The involved relationships were significantly interrelated (R2>0.942). Values b in the LWRs varied from 2.21 to 3.96 (mean ± SE: 3.15 ± 0.08). The student’s t-test showed that 87.9% of values b were significantly different from 3.; U ovom radu se prikazuje povezanost dužinsko-masenog odnosa i dužinsko-dužinskog odnosa za 21 vrstu riba ulovljenih u Izmirskom zaljevu. Koeficijenti a i b za odnos dužinsko-masenog (LWR) i odnos dužinsko-dužinskog (LLR) izračunati su s formulama W = a/b i kao jednadžbom TL = a + bFL i TL = a + bSL. Jednadžbe za pretvaranja standardne duljine i vilične duljine u ukupnu duljinu i obrnuto, pokazale su se linearnima. Uključeni odnosi bili su značajno međusobno povezani (R2>0,942). Vrijednosti b u LWR varirale su od 2,21 do 3,96 (srednja vrijednost ± SE: 3,15 ± 0,08). Stu-dentov t-test pokazao je da se 87,9% vrijednosti b značajno razlikuje od 3.