This article reports on a first attempt to develop and test run an observation procedure for assessing the syntactic and morphological development of adult learners of English as a second language (ESL) as evidenced in spontaneous speech production. The procedure is based on the profile analysis approach, which was first developed by Crystal, Fletcher, and Garman (1976) for the assessment of impaired speech (English) and later adapted to the assessment of second language development (German) by Clahsen (1985). The theoretical basis of the procedure is the multidimensional model of second language acquisition (SLA) developed by Meisel, Clahsen, and Pienemann (1981) and extended to ESL acquisition by Pienemann and Johnston (1987a). According to the model, invariant developmental stages in the acquisition of certain syntactic and morphological elements in German and English can be predicted and explained in terms of hierarchically ordered speech processing constraints. ln order to assess the developmental stage of ESL learners, an observation form was drawn up, incorporating a selection of morphosyntactic features whose presence or absence in a taped sample of natural speech was monitored by assessors. The ratings made by the assessors were then compared to those assigned through a detailed linguistic analysis to test the feasibility of using a “shorthand” version of a profile analysis. Analysis of the outcomes of the test run revealed significant correlations between the assessments and the linguistic analysis. But some variation was found in the assessors’ ability to apply the assessment criteria, and the extent of agreement between the assessors’ observations and the linguistic analysis was less than would be acceptable in the given theoretical framework. However, the source of these problems was identified through the first test run and suggestions were made for further refining the procedure to improve its accuracy.