Maddux (2–0) || Calvin Schiraldi (4–6) || Steve Bedrosian (13) || 30,812 || 34–41–1 |- |- style="background:#fbb" | 77 || July 1 || Reds || 3–5 || Tom Browning (7–3) || Shane Rawley (5–9) || John Franco (10) || 56,502 || 34–42–1 |- style="background:#bfb" | 78 || July 2 || Reds || 5–3 || David Palmer (4–6) || Jack Armstrong (0–3) || Steve Bedrosian (14) || 25,122 || 35–42–1 |- style="background:#fbb" | 79 || July 3 || Reds || 2–3 || Danny Jackson (9–4) || Kevin Gross (8–4) || None || 41,899 || 35–43–1 |- style="background:#fbb" | 80 || July 4 || @ Braves || 0–7 || Pete Smith (3–8) || Don Carman (4–5) || None || 23,921 || 35–44–1 |- style="background:#fbb" | 81 || July 5 || @ Braves || 5–10 || Jose Alvarez (3–2) || Bruce Ruffin (5–7) || None || 5,471 || 35–45–1 |- style="background:#fbb" | 82 || July 6 || @ Braves || 2–3 || Zane Smith (4–6) || Shane Rawley (5–10) || Bruce Sutter (12) || 6,537 || 35–46–1 |- style="background:#fbb" | 83 || July 7 || @ Reds || 2–5 || Danny Jackson (10–4) || Kevin Gross (8–5) || John Franco (12) || 31,910 || 35–47–1 |- style="background:#bfb" | 84 || July 8 || @ Reds || 1–0 || Don Carman (5–5) || José Rijo (9–4) || Steve Bedrosian (15) || 30,811 || 36–47–1 |- style="background:#fbb" | 85 || July 9 || @ Reds || 3–6 || Rob Dibble (1–0) || Kent Tekulve (2–5) || John Franco (13) || 29,473 || 36–48–1 |- style="background:#fbb" | 86 || July 10 || @ Reds || 4–5 || Jack Armstrong (1–3) || Shane Rawley (5–11) || John Franco (14) || 29,142 || 36–49–1 |- style="background:#bbcaff;" | – || July 12 ||colspan="7" |1988 Major League Baseball All-Star Game at Riverfront Stadium in Cincinnati |- style="background:#fbb" | 87 || July 14 || Astros || 5–7 || Juan Agosto (7–0) || Kent Tekulve (2–6) || Dave Smith (15) || 24,302 || 36–50–1 |- style="background:#fbb" | 88 || July 15 || Astros || 2–5 || Jim Deshaies (6–6) || Kevin Gross (8–6) || Danny Darwin (1) || 26,545 || 36–51–1 |- style="background:#bfb" | 89 || July 16 || Astros || 10–6 || Bruce Ruffin (6–7) || Danny Darwin (3–9) || None || 32,871 || 37–51–1 |- style="background:#bfb" | 90 || July 17 || Astros || 10–4 || Kent Tekulve (3–6) ||