Joining two tubes of different diameters has important concerns in many industries and engineering applications. An eccentric reducer is often used in such applications. Therefore, a simple and easy technique for manufacturing an eccentric reducer is of much importance. The simplest technique for producing the eccentric reducers is the tube nosing through eccentric conical dies. In this paper the finite element simulation is used to investigate the eccentric nosing of circular tubes through an eccentric conical die. Simulation is performed to investigate the plastic deformations of the deformed tube and all the possible modes of failure during the eccentric nosing process. Identification of unfavorable modes of failure in the tube nosing process lead to design modification guidelines, design of preform, and the die shape, for the eccentric nosing process. The results obtained confirmed that the modified design of the tube blank not only improves the quality of the nosed-tube product but also reduces nosing load and improves the limiting nosing ratio. Comparison with the experimental results shows that the nosing load and the modes of failure are successfully predicted by the finite element simulation. Also, a preform design for the tube blank that can produce an eccentric reducer with collar end that did not need a trimming process is introduced.