In two self-paced, sentence-by-sentence reading experiments, we examined the difference in the processing of Spanish discourses containing overt and null pronouns. In both experiments, antecedents appeared in a single phrase ("John met Mary") or in a conjoined phrase ("John and Mary met"). In Experiment 1, we compared reading times of sentences containing singular overt and null pronouns referring to the first or to the second mentioned antecedent. Overt pronouns caused a processing delay relative to null pronouns when they referred to the first antecedent in single but not in conjoined phrases. In Experiment 2, we compared reading times of sentences containing overt and null pronouns referring to singular or plural entities. Plural null pronouns were read faster than their singular counterparts in conjoined conditions. Plural overt pronouns were read more slowly than their null counterparts both in single and conjoined conditions. We explain our findings in a framework based on the notion of balance between processing cost and discourse function in line with the Informational Load Hypothesis.