Cy Young has lost the most career games, with 316 games.

Interpreted as:

active pitcher career most regular-season loss leader

	NAME	L	W	L%	G	W%	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	Cy Young C. Young	316	511	.382	906	.618	815	2.63	2,803	749	76	17	7356.0	7,092	2,147	3,167	138	1,217	161	84		29,565	156	3.43	1.49	2.30	0.17	9.5	4.1	1.13	.275	3.87	74	2.84	79	8.68	620
2	Pud Galvin P. Galvin	308	361	.460	697	.540	681	2.87	1,799	639	57	1	5941.1	6,352	1,895	3,315	121	744	54	18		25,160	220	2.73	1.13	2.42	0.18	7.2	3.0	1.19	.278	5.02	94	2.97	95	9.62	94.5
3	Nolan Ryan N. Ryan	292	324	.474	807	.526	773	3.19	5,714	222	61	3	5386.0	3,923	1,911	2,178	321	2,795	158	13	78	22,575	277	9.55	4.67	2.04	0.54	25.3	12.4	1.25	.265	3.64	90	2.96	83	6.56	370.2
4	Walter Johnson W. Johnson	279	417	.401	802	.599	666	2.17	3,509	531	110	34	5914.1	4,913	1,424	1,902	97	1,363	205	127		23,405	154	5.34	2.07	2.57	0.15	15.0	5.8	1.06	.264	2.89	68	2.42	76	7.48	472.8
5	Phil Niekro P. Niekro	274	318	.463	864	.537	716	3.35	3,342	245	45	29	5404.0	5,044	2,012	2,337	482	1,809	123	83	86	22,677	226	5.57	3.01	1.85	0.80	14.7	8.0	1.27	.270	3.89	87	3.61	95	8.40	116.1
6	Gaylord Perry G. Perry	265	314	.458	777	.542	690	3.11	3,534	303	53	10	5350.0	4,938	1,846	2,128	399	1,379	108	33	164	21,953	160	5.95	2.32	2.56	0.67	16.1	6.3	1.18	.275	3.58	85	3.06	85	8.31	312.9
7	Don Sutton D. Sutton	256	324	.441	774	.559	756	3.26	3,574	178	58	5	5282.1	4,692	1,914	2,104	472	1,343	82	12	102	21,631	112	6.09	2.29	2.66	0.80	16.5	6.2	1.14	.261	3.58	92	3.23	90	7.99	181.2
8	Jack Powell J. Powell	254	245	.509	578	.491	516	2.97	1,621	422	46	15	4389.0	4,319	1,450	1,991	110	1,021	120	57		17,896	67	3.32	2.09	1.59	0.23	9.1	5.7	1.22	.280	4.08	95	3.01	97	8.86	35
9	Eppa Rixey E. Rixey	251	266	.485	692	.515	554	3.15	1,350	290	37	14	4494.2	4,633	1,572	1,986	93	1,082	76	99		18,754	97	2.70	2.17	1.25	0.19	7.2	5.8	1.27	.281	3.98	88	3.29	91	9.28	162.7
10	Bert Blyleven B. Blyleven	250	287	.466	692	.534	685	3.31	3,701	242	60	0	4970.0	4,632	1,830	2,029	430	1,322	155	3	71	20,491	114	6.70	2.39	2.80	0.78	18.1	6.5	1.20	.282	3.67	85	3.18	82	8.39	368.6
11	Robin Roberts R. Roberts	245	286	.461	676	.539	609	3.41	2,357	305	45	25	4688.2	4,582	1,774	1,962	505	902	54	49	69	19,174	33	4.52	1.73	2.61	0.97	12.3	4.7	1.17	.265	3.77	89	3.50	91	8.80	179.6
12	Warren Spahn W. Spahn	245	363	.403	750	.597	665	3.09	2,583	382	63	28	5243.2	4,830	1,798	2,016	434	1,434	42	67	60	21,547	81	4.43	2.46	1.80	0.74	12.0	6.7	1.19	.258	3.46	84	3.44	94	8.29	124.4
13	Steve Carlton S. Carlton	244	329	.426	741	.574	709	3.22	4,136	254	55	2	5217.2	4,672	1,864	2,130	414	1,833	53	13	150	21,683	183	7.13	3.16	2.26	0.71	19.1	8.5	1.25	.279	3.67	87	3.14	86	8.06	271.5
14	Early Wynn E. Wynn	244	300	.449	691	.551	611	3.54	2,334	289	49	16	4564.0	4,291	1,796	2,037	338	1,775	64	67	36	19,408	51	4.60	3.50	1.31	0.67	12.0	9.1	1.33	.265	4.02	94	3.64	97	8.46	56.4
15	Jim Kaat J. Kaat	237	283	.456	898	.544	625	3.45	2,461	180	31	17	4530.1	4,620	1,738	2,038	395	1,083	122	102	116	19,023	128	4.89	2.15	2.27	0.78	12.9	5.7	1.26	.282	4.05	93	3.41	91	9.18	165.8
16	Frank Tanana F. Tanana	236	240	.496	638	.504	616	3.66	2,773	143	34	1	4188.1	4,063	1,704	1,910	448	1,255	129	10	116	17,641	119	5.96	2.70	2.21	0.96	15.7	7.1	1.27	.277	4.10	94	3.78	96	8.73	66.4
17	Gus Weyhing G. Weyhing	232	264	.468	540	.532	505	3.88	1,667	449	28	4	4337.0	4,576	1,872	2,796	120	1,570	277	34		19,188	240	3.46	3.26	1.06	0.25	8.7	8.2	1.42	.286	5.80	96	3.82	97	9.50	55.7
18	Tommy John T. John	231	288	.445	760	.555	700	3.34	2,245	162	46	3	4710.1	4,783	1,749	2,017	302	1,259	98	22	102	19,692	187	4.29	2.41	1.78	0.58	11.4	6.4	1.28	.284	3.85	90	3.37	89	9.14	208.3
19	Bob Friend B. Friend	230	197	.539	602	.461	497	3.58	1,734	163	36	10	3611.0	3,772	1,438	1,652	286	894	46	56	115	15,214	50	4.32	2.23	1.94	0.71	11.4	5.9	1.29	.284	4.12	94	3.35	89	9.40	172.2
20	Ted Lyons T. Lyons	230	260	.469	594	.531	484	3.67	1,073	356	27	25	4161.0	4,489	1,696	2,056	222	1,121	31	91		17,797	55	2.32	2.42	0.96	0.48	6.0	6.3	1.35	.278	4.45	85	4.01	95	9.71	91.7
21	Greg Maddux G. Maddux	227	355	.390	744	.610	740	3.16	3,371	109	35	0	5008.1	4,726	1,756	1,981	353	999	137	3	177	20,421	70	6.06	1.80	3.37	0.63	16.5	4.9	1.14	.281	3.56	76	3.25	78	8.49	519.5
22	Fergie Jenkins F. Jenkins	226	284	.443	664	.557	594	3.34	3,192	267	49	7	4500.2	4,142	1,669	1,853	484	997	84	37	116	18,400	62	6.38	1.99	3.20	0.97	17.3	5.4	1.14	.268	3.71	87	3.27	88	8.28	222.9
23	Red Ruffing R. Ruffing	225	273	.452	624	.548	538	3.80	1,987	335	45	18	4344.0	4,284	1,833	2,115	254	1,541	58	69		18,546	46	4.12	3.19	1.29	0.53	10.7	8.3	1.34	.274	4.38	91	3.93	95	8.88	82.3
24	Tim Keefe T. Keefe	225	342	.397	600	.603	594	2.63	2,564	554	39	2	5049.2	4,438	1,474	2,470	75	1,233	83	7		20,941	240	4.57	2.20	2.08	0.13	12.2	5.9	1.12	.257	4.40	79	2.92	87	7.91	239.2
25	Bobo Newsom B. Newsom	222	211	.513	600	.487	483	3.98	2,082	246	31	21	3759.1	3,769	1,664	1,908	206	1,732	61	71		16,467	60	4.98	4.15	1.20	0.49	12.6	10.5	1.46	.288	4.57	95	3.81	92	9.02	144.5