Barry Bonds has the most career bases on balls in the month of April, with 338 bases on balls.

	NAME	BB	G	AB	R	H	2B	3B	HR	RBI	HBP	SO	SB	CS	PA	TB	XBH	SH	SF	IBB	GIDP	AVG	OBP	SLG	OPS
1	Barry Bonds B. Bonds	338	407	1,345	314	394	88	11	117	293	20	202	64	11	1,714	855	216	0	11	100	22	.293	.439	.636	1.074
2	Rickey Henderson R. Henderson	331	411	1,470	313	394	74	13	39	153	14	227	172	52	1,821	611	126	0	6	11	16	.268	.406	.416	.821
3	Jim Thome J. Thome	276	387	1,256	233	331	68	7	77	233	16	382	1	4	1,557	644	152	0	9	37	27	.264	.400	.513	.913
4	Joe Morgan J. Morgan	275	361	1,295	232	354	66	17	33	162	7	128	108	26	1,599	553	116	6	16	9	14	.273	.399	.427	.826
5	Frank Thomas F. Thomas	272	362	1,288	211	361	77	4	69	246	15	214	7	7	1,597	653	150	0	22	20	41	.280	.406	.507	.913
6	Gary Sheffield G. Sheffield	260	439	1,565	273	435	83	8	84	258	29	209	46	21	1,876	786	175	2	20	28	49	.278	.386	.502	.889
7	Albert Pujols A. Pujols	247	490	1,823	318	508	100	1	118	361	20	227	16	9	2,106	964	219	0	16	59	67	.279	.368	.529	.897
8	Adam Dunn A. Dunn	232	300	1,017	184	253	48	3	75	177	13	358	14	4	1,266	532	126	0	4	17	12	.249	.393	.523	.916
9	Jeff Bagwell J. Bagwell	229	330	1,212	232	371	71	6	75	242	18	238	29	19	1,474	679	152	1	14	17	35	.306	.420	.560	.980
10	Todd Helton T. Helton	223	347	1,225	230	364	97	7	47	231	10	169	4	3	1,471	616	151	0	13	26	27	.297	.406	.503	.909
11	Jason Giambi J. Giambi	222	364	1,232	194	332	56	2	69	241	34	257	2	4	1,504	599	127	0	16	14	27	.269	.391	.486	.877
12	Wade Boggs W. Boggs	220	314	1,180	176	356	71	3	10	119	2	113	4	7	1,420	463	84	4	14	25	23	.302	.408	.392	.801
13	Joey Votto J. Votto	216	339	1,197	175	331	68	4	54	180	19	288	15	7	1,441	569	126	0	9	21	33	.277	.393	.475	.868
14	Chipper Jones C. Jones	212	367	1,345	243	420	80	5	71	270	1	201	18	3	1,570	723	156	0	12	20	40	.312	.403	.538	.941
15	Bobby Abreu B. Abreu	210	364	1,320	207	375	88	6	37	194	7	277	56	18	1,554	586	131	1	16	7	32	.284	.381	.444	.825
16	Dwight Evans D. Evans	209	344	1,222	189	313	62	14	39	162	6	217	15	8	1,450	520	115	3	10	5	31	.256	.365	.426	.790
17	John Olerud J. Olerud	206	318	1,111	186	359	88	0	41	191	15	150	3	2	1,352	570	129	5	15	25	42	.323	.431	.513	.944
18	Carlos Santana C. Santana	204	316	1,135	166	260	58	0	43	168	7	225	15	3	1,353	447	101	0	7	11	27	.229	.348	.394	.742
19	Manny Ramirez M. Ramirez	203	369	1,379	243	437	84	6	87	312	11	274	6	1	1,608	794	177	1	14	32	49	.317	.405	.576	.981
20	Rafael Palmeiro R. Palmeiro	203	387	1,446	240	408	89	5	70	265	10	185	23	4	1,683	717	164	2	22	14	31	.282	.369	.496	.865
21	Carl Yastrzemski C. Yastrzemski	203	358	1,336	190	365	79	9	47	214	7	149	29	14	1,559	603	135	1	12	25	42	.273	.369	.451	.820
22	Ken Griffey Jr. K. Griffey Jr.	202	412	1,482	239	405	73	8	90	276	12	267	28	10	1,714	764	171	2	16	44	31	.273	.362	.516	.877
23	Fred McGriff F. McGriff	202	366	1,321	199	376	67	3	65	226	4	300	13	5	1,538	644	135	1	10	21	36	.285	.379	.488	.866
24	Bryce Harper B. Harper	201	269	951	189	269	61	4	64	185	6	244	22	12	1,167	530	129	0	9	34	24	.283	.408	.557	.965
25	Mark McGwire M. McGwire	201	249	828	167	228	45	0	77	199	10	207	2	1	1,050	504	122	1	10	17	23	.275	.418	.609	1.027