Here, Cds Nanoclusters Have Been Synthesized Using a Chemical Route. Structural and Morphological Analyses Have Been Done Using X-Ray Diffraction (Xrd) and Transmission Electron Microscopy (Tem). Synthesized Nanoclusters Are Used to Prepare the Cds - Ethylene Glycol Nanofluids, at Three Different Concentrations of Cds (Viz 0.2 Vol, 0.6 Vol and 1.0 Vol), Using Ultrasonication Method. Size Distribution Profile of the Suspended Particles Is Analysed By an Acoustical Particle Sizer (Aps-100), Based on the Ultrasonic Spectroscopic Technique. the Crystallite Size Obtained from Xrd Is Compared With the Particle Size Estimated from the Tem and Aps -100 Techniques and a Proper Rationale Is Provided For the Differences In Measurements. Frequency-Dependent Ultrasonic Attenuations at Different Concentrations of Dispersed Nanoparticles In the Nanofluids Have Been Measured By Aps-100. the Ultrasonic Wave Exhibits a Nonlinear Increase In Ultrasonic Attenuation With Frequency In All the Samples of Nanofluids. the Analysis of the Observed Results Enables Us to Understand the Interaction of the Ultrasonic Wave With the Suspended Nanoparticle In the Nanofluids System.