Between the 1980 and 1989 seasons, Fernando Valenzuela won the most games by a left-hander, with 128 wins.

Interpreted as:

most regular-season wins left handed pitcher 80s

	NAME	W	L	W%	G	GS	ERA	SO	CG	SHO	SV	IP	H	ER	R	HR	BB	HBP	GF	IBB	TBF	WP	K/9	BB/9	K/BB	HR/9	K%	BB%	WHIP	BABIP	RA	ERA-	FIP	FIP-	H/9	PRAA
1	Fernando Valenzuela F. Valenzuela	128	103	.554	298	287	3.19	1,644	102	27	2	2144.2	1,876	760	869	133	838	16	5	54	8,957	81	6.90	3.52	1.96	0.56	18.4	9.4	1.27	.276	3.65	91	3.21	90	7.87	84
2	Frank Viola F. Viola	117	98	.544	272	271	3.84	1,287	56	11	0	1858.0	1,850	792	877	218	548	30	0	20	7,801	48	6.23	2.65	2.35	1.06	16.5	7.0	1.29	.285	4.25	91	3.83	94	8.96	46.2
3	Floyd Bannister F. Bannister	112	109	.507	297	294	3.98	1,356	50	11	0	1890.2	1,813	836	929	234	616	28	0	23	7,994	66	6.45	2.93	2.20	1.11	17.0	7.7	1.28	.274	4.42	96	3.94	96	8.63	35.4
4	Ron Guidry R. Guidry	111	72	.607	252	232	3.66	1,126	55	10	1	1639.2	1,599	666	719	180	412	11	9	21	6,800	33	6.18	2.26	2.73	0.99	16.6	6.1	1.23	.280	3.95	92	3.56	89	8.78	80
5	Scott McGregor S. McGregor	107	83	.563	262	247	4.13	668	62	17	0	1604.1	1,727	736	799	189	413	16	7	21	6,797	20	3.75	2.32	1.62	1.06	9.8	6.1	1.33	.279	4.48	104	4.23	104	9.69	-31.2
6	Frank Tanana F. Tanana	107	122	.467	314	304	3.89	1,225	51	8	0	1994.0	2,014	861	989	219	589	55	3	59	8,493	55	5.53	2.66	2.08	0.99	14.4	6.9	1.31	.280	4.46	97	3.91	97	9.09	27
7	Bob Knepper B. Knepper	105	118	.471	332	306	3.70	1,068	50	20	1	2005.1	2,045	824	946	167	597	36	8	52	8,484	39	4.79	2.68	1.79	0.75	12.6	7.0	1.32	.284	4.25	107	3.70	107	9.18	-64.6
8	Jerry Reuss J. Reuss	105	83	.559	300	258	3.48	762	44	17	5	1688.0	1,724	652	755	123	379	23	23	51	7,035	33	4.06	2.02	2.01	0.66	10.8	5.4	1.25	.279	4.03	95	3.49	95	9.19	28.2
9	Steve Carlton S. Carlton	104	84	.553	254	240	3.48	1,453	54	13	1	1732.1	1,604	670	774	135	631	12	6	50	7,271	76	7.55	3.28	2.30	0.70	20.0	8.7	1.29	.291	4.02	92	3.18	85	8.33	100.4
10	John Tudor J. Tudor	104	66	.612	250	235	3.13	914	48	15	1	1622.2	1,518	564	629	144	436	27	5	27	6,665	18	5.07	2.42	2.10	0.80	13.7	6.5	1.20	.267	3.49	81	3.62	96	8.42	23.6
11	Mike Flanagan M. Flanagan	103	94	.523	278	276	4.01	845	49	10	0	1740.0	1,801	776	846	170	568	25	1	25	7,400	57	4.37	2.94	1.49	0.88	11.4	7.7	1.36	.282	4.38	101	4.06	101	9.32	-6.1
12	Bruce Hurst B. Hurst	103	84	.551	270	250	4.01	1,222	64	15	0	1703.2	1,783	759	831	189	545	24	5	31	7,254	38	6.46	2.88	2.24	1.00	16.8	7.5	1.37	.302	4.39	96	3.76	94	9.42	41.4
13	Shane Rawley S. Rawley	102	100	.505	369	225	4.02	877	41	7	25	1675.2	1,732	749	820	144	643	22	87	56	7,215	45	4.71	3.45	1.36	0.77	12.2	8.9	1.42	.287	4.40	104	4.01	105	9.30	-31.7
14	John Candelaria J. Candelaria	97	69	.584	274	212	3.50	971	22	6	14	1400.0	1,379	544	604	129	303	20	36	24	5,742	13	6.24	1.95	3.20	0.83	16.9	5.3	1.20	.289	3.88	91	3.25	85	8.87	88.4
15	Tommy John T. John	96	89	.519	273	254	4.01	523	50	10	0	1628.0	1,864	726	812	119	397	37	9	27	6,949	66	2.89	2.19	1.32	0.66	7.5	5.7	1.39	.297	4.49	101	3.85	95	10.30	35.5
16	Charlie Leibrandt C. Leibrandt	92	78	.541	273	229	3.78	723	40	13	2	1568.1	1,652	658	727	121	476	20	16	29	6,674	46	4.15	2.73	1.52	0.69	10.8	7.1	1.36	.287	4.17	94	3.78	97	9.48	23.7
17	Bob Ojeda B. Ojeda	88	73	.547	242	210	3.65	822	37	14	1	1364.2	1,301	553	615	106	458	18	17	27	5,725	18	5.42	3.02	1.79	0.70	14.4	8.0	1.29	.277	4.06	94	3.59	95	8.58	27.7
18	Mark Langston M. Langston	86	76	.531	200	197	3.80	1,253	47	13	0	1374.1	1,206	580	653	146	668	26	1	16	5,866	39	8.21	4.37	1.88	0.96	21.4	11.4	1.36	.281	4.28	91	3.84	92	7.90	56
19	Rick Honeycutt R. Honeycutt	79	101	.439	359	213	3.62	700	35	9	20	1501.0	1,529	603	703	122	431	28	49	49	6,314	30	4.20	2.58	1.62	0.73	11.1	6.8	1.31	.280	4.22	96	3.78	99	9.17	2.5
20	Teddy Higuera T. Higuera	78	44	.639	154	152	3.28	857	46	11	0	1085.0	941	395	431	96	331	18	2	13	4,451	11	7.11	2.75	2.59	0.80	19.3	7.4	1.17	.268	3.58	78	3.30	81	7.81	92.8
21	Tom Browning T. Browning	78	52	.600	185	184	3.72	675	26	10	0	1211.1	1,141	501	552	149	337	19	1	34	5,017	12	5.02	2.50	2.00	1.11	13.5	6.7	1.22	.259	4.10	98	4.12	108	8.48	-38.6
22	Jimmy Key J. Key	74	49	.602	224	157	3.36	614	22	6	10	1115.0	1,043	416	459	109	279	16	24	20	4,570	25	4.96	2.25	2.20	0.88	13.4	6.1	1.19	.263	3.70	81	3.73	91	8.42	46.6
23	Steve Trout S. Trout	74	84	.468	263	215	4.21	569	25	7	0	1324.0	1,481	620	704	80	508	28	12	43	5,776	49	3.87	3.45	1.12	0.54	9.9	8.8	1.50	.305	4.79	106	3.88	98	10.07	13.3
24	Dave Righetti D. Righetti	73	59	.553	466	73	3.08	884	13	2	188	1066.1	941	365	417	55	437	14	332	35	4,509	31	7.46	3.69	2.02	0.46	19.6	9.7	1.29	.284	3.52	78	3.01	76	7.94	114.9
25	Dave LaPoint D. LaPoint	73	75	.493	264	198	3.96	732	9	4	1	1324.0	1,408	583	654	106	496	15	17	44	5,745	49	4.98	3.37	1.48	0.72	12.7	8.6	1.44	.296	4.45	107	3.84	103	9.57	-17