The New York Mets had the lowest run differential by a team in 1963, with a differential of -273 runs.

	TEAM	DIFF	SEASON	G	W%	W	L	AB	R	H	2B	3B	HR	RBI	BB	HBP	SO	SB	CS	PA	TB	XBH	SH	SF	IBB	GIDP	AVG	OBP	SLG	OPS
1	Mets	-273	1963	162	.315	51	111	5,336	501	1,168	156	35	96	459	457	47	1,078	41	52	5,921	1,682	287	46	35	41	106	.219	.285	.315	.600
2	Senators	-234	1963	162	.346	56	106	5,446	578	1,237	190	35	138	538	497	30	963	68	28	6,069	1,911	363	57	39	35	111	.227	.293	.351	.644
3	Colt .45's	-176	1963	162	.407	66	96	5,384	464	1,184	170	39	62	420	456	30	938	39	30	5,983	1,618	271	86	27	39	119	.220	.283	.301	.584
4	Athletics	-89	1963	162	.451	73	89	5,495	615	1,356	225	38	95	582	529	25	829	47	26	6,172	1,942	358	77	46	47	125	.247	.313	.353	.667
5	Indians	-67	1963	162	.488	79	83	5,496	635	1,314	214	29	169	592	469	40	1,102	59	36	6,136	2,093	412	88	43	46	105	.239	.301	.381	.682
6	Angels	-63	1963	161	.435	70	91	5,506	597	1,378	208	38	95	551	448	43	916	43	30	6,127	1,947	341	84	46	43	110	.250	.309	.354	.663
7	Red Sox	-38	1963	161	.472	76	85	5,575	666	1,403	247	34	171	623	475	26	954	27	16	6,145	2,231	452	44	25	40	138	.252	.312	.400	.712
8	Pirates	-28	1963	162	.457	74	88	5,536	567	1,385	181	49	108	523	454	29	940	57	41	6,110	1,988	338	63	28	47	137	.250	.309	.359	.668
9	Cubs	-8	1963	162	.506	82	80	5,404	570	1,286	205	44	127	530	439	36	1,049	68	60	5,987	1,960	376	64	44	57	112	.238	.297	.363	.660
10	Tigers	-3	1963	162	.488	79	83	5,500	700	1,388	195	36	148	648	592	38	908	73	32	6,242	2,099	379	64	48	49	127	.252	.327	.382	.708
11	Orioles	23	1963	162	.531	86	76	5,448	644	1,359	207	32	146	609	469	28	940	97	34	6,055	2,068	385	73	37	43	119	.249	.310	.380	.690
12	Reds	54	1963	162	.531	86	76	5,416	648	1,333	225	44	122	608	474	47	960	92	58	6,040	2,012	391	62	41	52	95	.246	.310	.371	.682
13	Phillies	64	1963	162	.537	87	75	5,524	642	1,390	228	54	126	599	403	44	955	56	39	6,092	2,104	408	87	34	64	99	.252	.306	.381	.687
14	Braves	74	1963	163	.519	84	78	5,518	677	1,345	204	39	139	624	525	43	954	75	52	6,211	2,044	382	82	43	63	108	.244	.312	.370	.683
15	Giants	84	1963	162	.543	88	74	5,579	725	1,442	206	35	197	680	441	45	889	55	49	6,176	2,309	438	72	39	53	125	.258	.316	.414	.730
16	Dodgers	90	1963	163	.611	99	63	5,428	640	1,361	178	34	110	584	453	26	867	124	70	6,045	1,937	322	85	53	47	121	.251	.309	.357	.666
17	Cardinals	119	1963	162	.574	93	69	5,678	747	1,540	231	66	128	697	458	25	915	77	42	6,283	2,287	425	85	37	51	95	.271	.326	.403	.729
18	White Sox	139	1963	162	.580	94	68	5,508	683	1,379	208	40	114	648	571	40	896	64	28	6,242	2,009	362	79	44	29	97	.250	.323	.365	.688
19	Twins	165	1963	161	.565	91	70	5,531	767	1,408	223	35	225	722	547	41	912	32	14	6,233	2,376	483	84	30	41	116	.255	.325	.430	.754
20	Yankees	167	1963	161	.646	104	57	5,506	714	1,387	197	35	188	666	434	31	808	42	26	6,067	2,218	420	66	30	46	91	.252	.309	.403	.711