Length-length and length-weight relationships are of particular interest to fishery managers and scientists. These relationships can be used to estimate critical information for a given species of finfish, such as converting several types of length measurements to a common type or calculating average weights of a given species at a particular length. The ability to use these relationships to calculate a common length type from different length types recorded in different databases, or average weights for specified lengths allows the use of data that may not contain all information needed for various modeling procedures. Of additional interest is the ability to determine the difference in the length of species that have been measured by total length methods of compressing the tail or relaxing the tail. These differences can be substantial in species that have forked tails. These differences may be important when establishing minimum size regulations based on length at maturity or for enforcement purposes if total length is not specifically defined. Four different length-length relationships for more than forty species of finfish from recreational and commercial fishing catches as well as length-weight relationships for the same species caught in Florida waters will be presented.