Uniformity of condensed layers of DT fuel in cryogenic ICF targets is a crucial parameter in their design. Measurement by classical interferometry lacks resolution to determine DT layer uniformity for targets with thick glass shells and/or thick ablative polymer coatings. We have developed holographic interferometry as an alternative tool for layer uniformity determination. This method is sensitive only to the fuel layer itself. This paper describes the technique and interference pattern analysis, and also presents preliminary results.