Purpose: To test the proposal that the tense deficit that has been demonstrated for children with specific language impairment (SLI) in other languages is also found in child Spanish and that low performance on tense-related measures can distinguish Spanish-speaking children with SLI from those without. Method: The authors evaluated evidence from existing spontaneous production, elicited production, and grammaticality judgment studies of finiteness in child Spanish. They measured the relationship of 7 spontaneous speech measures with previous receptive and expressive measures of finiteness and performed a discriminant function analysis, using tense as the target variable, to classify monolingual child Spanish (n = 55) as representing SLI or as typically developing (TD). Results: Spontaneous speech measures correlated with the results of previous receptive and expressive measures of child Spanish that show a tense deficit. The SLI group was shown to have statistically lower scores than the TD group on 6 of 7 spontaneous speech measures. Multiple discriminant functions, including tense measures by themselves and in combination with spontaneous speech measures, were shown to provide fair to good sensitivity and specificity in the classification of children as having SLI vs. TD. Conclusion: The findings support the contention that the tense-marking deficit is a plausible clinical marker of SLI for Spanish-speaking children.