NiFe thin film alloys with nanometer-scale spatially periodic composition modulations have been electrodeposited in the uniform injection cell (UIC) by oscillating the electrolyte flow rate. [See, Medina and Schwartz, J. Electrochem. Soc. 142, 451, 457, L46 (1995) for a description of the UIC.] The flow-induced composition modulated alloys were made using flow oscillation frequencies omega less than or equal to 0.05 Hz and galvanostatic deposition at -10 mA cm(-2). Flow-induced periodicity wavelengths (Lambda) as small as 55 nm were measured using stripping voltammetry. The experimental results showed that Lambda had the expected inverse dependence on the flow oscillation frequency. The electrochemical response of the NiFe plating system was found to be out of phase with the low frequency (quasi-steady) flow modulations, a result that reiterates the anomalous nature of NiFe codeposition and the important role that careful hydrodynamic impedance studies could possibly play in analyzing the system.