The paper analyses and compares alternative iterative and recursive implementations of FPGA circuits for various problems. Two types of recursive calls have been examined, namely for cyclic and binary (N-ary) search algorithms. The details of experiments are presented for four different design problems. The relevant comparative data have been obtained as a result of synthesis and implementation in FPGAs of the respective circuits from system-level (Handel-C) and RTL (VHDL) specifications.