Purple loosestrife (Lythrum salicaria) is an invasive wetland perennial that is thought to threaten the ecological integrity of North American wetlands by forming monotypic stands and altering the diversity of native wetland ecosystems. To determine if purple loosestrife infestation alters aquatic invertebrate communities, the abundance and size distribution of aquatic invertebrates associated with purple loosestrife were quantified during the spring and summer and compared to those within stands of two other commonly occurring emergents, cattail (Typha latifolia) and bulrush (Scirpus acutus). Aquatic invertebrates representing 10 taxa (classes or orders) were collected using four different sampling techniques. Individuals from each taxa were collected in all three vegetation types, although the size of the individuals of some orders was smaller in Lythrum. Measurements of water quality indicated no significant (p ≤ 0.05) differences among the three vegetation types, despite the fact that Scirpus tended to be established in deeper water than Lythrum. Results indicate that monotypic stands of purple loosestrife are not lacking in aquatic invertebrates; however, because our study was conducted in a mixed vegetation wetland at an intermediate stage of purple loosestrife infestation, our findings may not be representative of more extreme purple loosestrife invasions.