The development of the English as a Second Language Assessment Battery (ESLAB) was based on needs indicated by achievement and placement statistics. The selection of the proficiency skills (listening, speaking, reading, and writing) was supported by changing views in language assessment and by legislation. Andrew D. Cohen's language model was adapted as a theoretical frame of reference. The battery was developed with a recognition of the interrelationship of native and second language skills. Receptive and expressive components of ESLAB included the Oral Screening Test, Oral Competency Test, Aural Comprehension Test, Dictation Exercise, Structural Competency Test, and Informal Reading Inventory. To ascertain ESLAB's statistical stability, 59 Hispanic inner-city bilingual students in grades 7 and 8 were tested. Each of the tests was subjected to item analysis, involving item difficulty and item discrimination. Face, content, predictive, and concurrent validity were established. Internal consistency and interrater correlations for the expressive subtests were also attained. Overall, both the receptive and expressive subtests of the ESLAB pilot edition proved to be valid and reliable measures of language proficiency. (Author/GDC)