Irregular Conjugations in the Present Subjunctive

There are two main categories of irregular verbs in the present subjunctive: fully irregular verbs and stem-changing verbs. Fortunately, you are probably already familiar with these changes, as they also occur in the present indicative and formal commands.

Fully Irregular Verbs in the Present Subjunctive

Rule 1. The following verbs are irregular in the present subjunctive: ser, estar, ir, haber, saber, dar. You will have to learn them through memorization. These verbs are conjugated in the present subjunctive below, with examples using common subjunctive phrases.

Stem Changes Similar to the Present Indicative

As mentioned in the introduction, the stem changes that occur in the present indicative also occur in the present subjunctive -- with slight variations.

Rule 2. The group of verbs ending in -ducir that have changes in the first-person present indicative, such as conducir (conduzco), introducir (introduzco), reducir (reduzco), reproducir (reproduzco), producir (produzco), etc.*, have the same change in the present subjunctive. But, in this case, this change will apply for all the persons.

Here is an example with the verb conducir, so you can see a side-by-side comparison.

Rule 3. In the present indicative, there are stem-changing verbs (e to i, e to ie and u to o). Click here for a refresher on this topic. These verbs follow the same pattern in the present subjunctive. However, some of them have an additional change in the nosotros and vosotros forms.

Changes e → i

Here is an example with the verb competir. Notice the additional change in nosotros and vosotros in the present subjunctive.

Changes o → ue

Here is an example with the verb dormir. Notice the additional change in nosotros and vosotros in the present subjunctive.

Changes e → ie

Here is an example with the verb cerrar. Here, there are no changes in the nosotros and vosotros form.

Spelling Changes Similar to Formal Commands

Rule 4. Formal commands of verbs whose infinitives end in -car, -gar, and -zar -- such as buscar, cargar, and empezar -- have spelling changes to keep the sound of the infinitive form. These same spelling changes occur in the present subjunctive as well.

For example, the formal command of the verb buscar is busque. Use this spelling change when conjugating buscar in the present subjunctive.