Two male figures stand side by side against a dark, neutral background, each wrapped in voluminous cloaks. The figure on the left, with gray hair and beard, looks toward his companion with a gentle, contemplative expression. His right hand gestures outward, palm open, while his left hand rests near his waist, fingers curling around the edge of his cloak.

The figure on the right, bald on top with a dark beard, faces forward with a more intense, direct gaze. He wears a cloak in vivid red and ochre tones, and his left hand points to an open book resting on the table before him. Both figures are set close to the picture plane, their forms filling most of the canvas and overlapping slightly in the center.

The light falls from the left, illuminating their faces, hands, and the folds of their garments, while casting shadows behind them and across the background. The open book at the lower right edge of the painting displays lines of text, its pages slightly curved, and a dark inkpot sits nearby on the table. The brushwork is visible in the textured rendering of the hair, beards, and the swirling drapery, with loose, energetic strokes especially apparent in the red folds.

The composition is anchored by the strong diagonals of the arms and the contrasting colors of the cloaks, with ochre and red dominating the palette. A vertical band of lighter brown runs down the background between the two figures, separating the darker areas behind each man. The upper left and right corners of the painting are filled with deep, shadowy brown tones, with no discernible objects or details.

The light highlights the creases and sharp edges of the red cloak, creating a dramatic contrast with the shadowed areas underneath the arm. Fine, dark outlines define the contours of the hands and facial features, while the paint is applied more loosely in the backgrounds and drapery. Saints Peter and Paul is painted by El Greco in 1587.