MicroRNAs (miRNAs) are small RNA molecules that regulate gene expression by targeting messenger RNAs and causing cleavage or translation blockage. miRNAs induced after parasitization of the lepidopteran host Lymantria dispar by the parasitoid wasp Glyptapanteles flavicoxis, which introduces a polydnavirus and other parasitoid factors, were examined to identify induced miRNAs that might regulate host genes and contribute to host immunosuppression and other effects. miRNA profiling of parasitized larval hemocytes versus non-parasitized ones by microarray hybridization to mature insect and virus miRNAs identified 27 differentially expressed miRNAs after parasitization. This was confirmed by real-time relative qPCR for insect miRNAs (dme-mir-1, -8, -14, -184, -276, -277, -279, -289, -let-7) using miRNA-specific TaqMan assays. Certain cellular miRNAs were differentially expressed in larval tissues, such as the potentially developmentally linked mir-277, signifying a need for functional studies.